Vintage DD turntables. Are we living dangerously?

I am as well experiencing a similar excitement for Vintage DD's,
I have been slowly bringing a Plan to the forefront to be undertaken

As part of my owned, but not used 'Daily' TT;s I have 2x TTS-8000
2x DP-80 and 2x Aurex SR-510;s.

I have a design in place to exchange an amount of the Original used parts on the TTS 8000 with a seen to be improved materials.

Some the most important exchanged components are to be produced in Duplicate from similar materials that are composites, and known for their stability to perform without change in any ambient environment and will remain unchanged in their properties when used on a TT.
The Duplicate Parts with have a variance in their Shore Hardness Scales readings, these Parts will then further allow for a fine tuning of a Attenuation when the TT is set up in its permanent set up.

The End User will (if wanted) be able to make some slight alterations to the Presentation of the TT, by swapping out a Part that has a Identical composite of materials, but produced to have a change in a property at the time of Manufacture to be a material that can be optimised for certain types of application.

I can then make a plan for the Other TT's if this Design Change to the
TT-8000 is seen as a improvement over the standard model.
As I am not seeing any restrictions on any of the the Stripped Back TT's that suggest the TTS redesign is limited to that model only.

There is a Plinth design Drawn Up as well, which is going to allow for a TT to be mounted in a Plinth that can be inserted into a Substantial Permali Support, in which the Tonearm is attached to.
This will allow for the TT Trials -
Original Model vs Exchanged Parts Model - to be carried out in with the exact same Tonearm Cartridge and be exposed to an identical Impact from the Ambient Environment.

When all this intention comes to fruit, and I have selected DD TT's from the group that have been the most impressive.
I can then produce a Plinth to be inserted for my other TT's be it Idler or Belt and carry on with a furthering of the comparison trials.

Obviously the above has a not so common approach to a
Preparation and Investigation into a Experimentation with a whole range of TT's used in a Standardised Set Up.

One of the parts used in the Standardised Set Up will be one of my sets of the AT-616 Pneumatic Footers, as these have lest a good impression on me for a Long Time    

Have a question for you experts, just remember I am learning about analog and some things I might get it wrong.
Just recently acquired a PD-444, the ability of mounting 2 tonearms and looked in good condition it made it hard to pass by, still waiting for it to be delivered. I've got an EPA-100 mk2 for it with an SH-100, as I understand it this is a Medium to High mass tonearm which would benefit from moderate to low compliance cartridges.
For alignment, what do you guys recommend? the tonearm original mounting template is at $120 on Ebay which is nice but a racket IMO. I've got the protractor that comes with the Hifi News record but seems to be Bearwalds whether this specific and most japanese arms are Stevenson.
Raul posted that some tonerarm alignments even the manufacturer got it wrong (was it Saec?)
So my question would be which type of alignment should I follow?
P2S is 250mm and Overhang 15mm
Any specific method to test the bearings?
Any cartridge recommended for it?
As a second tonearm for the PD-444 what should I look for? MA-505LS? FR-64s or 66s? apparently the SAEC's and Victors are not that good as the FR and MA per previous comments. Just trying to look for a versatile tonearm different than the EPA-100?Note I also have a 1200mk5 Technics with medium mass tonearm.
Thank you in advance for your answers, I'm excited with learning and rediscovering vinyl.
Raul, looking forward to your comments (bad or good) I won't complain, your experience is legendary
Chak, of course I'm interested on your comments tooLew and Nandric, I respect you immensely, you guys make a lot of sense.
All the best
Luis

Just recently acquired a PD-444, the ability of mounting 2 tonearms and looked in good condition it made it hard to pass by, still waiting for it to be delivered. I’ve got an EPA-100 mk2

Luis, unfortunately you can’t mount EPA-100 mkII on Luxman "armboard", it’s impossible, required hole for the tonearm base is too big (actually it’s huge). I have EPA-100 mkII too.

Any Technics tonearm with that huge base (like EPA-500) is not compatible with Luxman base.

But earlier EPA-100 (not mk2) is fine for Luxman.

As a second tonearm for the PD-444 what should I look for? MA-505LS? FR-64s or 66s? apparently the SAEC’s and Victors are not that good as the FR and MA per previous comments. Just trying to look for a versatile tonearm different than the EPA-100? Note I also have a 1200mk5 Technics with medium mass tonearm.
Thank you in advance for your answers, I’m excited with learning and rediscovering vinyl.

Actually Victor are perfect, but you need a NOS sample, not broken junk. I think Victor 7045 and 7082 are excellent tonearms for very reasonable price, but again, you need to find absolutely perfect sample.

Fidelity-Research are fine, I have 64fx with n60 and 64s with b60. But I’m using them only with low compliance cartridges.

Another arm is Lustre GST-801 which I have on my PD-444 for a long time, great tonearm for the money (with great features, this is a nice arm for many cartridges), much more reasonable priced than Fidelity-Research.

P.S. Welcome to the Luxman club!
For your PD-444 try SAEC SS-300 mat, Micro Seiki CU-180, or modern Sakura System's THE MAT. 

Thank you @chakster , for the tips. I'm excited rediscovering analog, my 1200mk5 which supposedly is not an audiophile class TT sounds great compared to my digital, I would say different. I can only imagine the possibilities with the PD-444 and two good tonearms and carts.

If you have access to a woodworker and machinist, it's not hard to expand a PD444 with a partial subplinth and third arm base out front.  I did that with a thick wenge wood subplinth and a brass pillar that accepts standard Micro Seiki brass cantilever armboards.  This frees you to add whatever arm you like.  If interested, feel free to PM me for pictures.   The dense wenge actually dampens the entire TT and improves the performance of all three arms.