where to install a tonearm

Hi, Until today I always thought that all that I need to set up a tonearm is to use a protractor to find the "pivot to splidle" distance and that's it. If I want I can draw an arc with this information and I can install it anywhere in that arc.
I have a Lustre GST-801 to install and in the manual found that besides showing you the correct distances, they include 2 more measurements: they draw a line that goes from the center pivot up to the point when it connects with the extension of the horizontal line of the spindle (basically where both lines meet in a 90 degrees angle). in the Lustre, those distances 199mm (horizontal) and 105mm (vertical). If I take this into consideration the arm will be too close to the platter (my TT has a peripherial ring) and that's not practical for me.
knowing that a platter is round I always though that we can install the arm anywhere in the arc line that I mentioned before ... am I correct?, am I wrong?, please help me with this, Im really confused.
I just checked the manual on Vinyl Engine and;

Your arm has effective length of 240mm and overhang of 15mm, so mounting distance (pivot to spindle) is 240-15= 225mm.

You can put your tonearm around the platter wherever position you want as long as it is mounting hole center is 225mm from platter spindle.If you have a plinthless turntable and seperate arm pod your choice is wherever you want, if your turntable has a plinth you should choose a mounting place;
a-which is inside the borders of the plinth
b-if you usea any lid, care not to obstruct it's use
c-not too front because it increases the possibility of accidental stylus damage
d- aestethics

So, drill a hole 38-39mm diameter which it's center is 225mm from spindle then check the arm for 105mm. and 199mm which means the arm rest part will face at the right angle to front.I think these numbers are for the tonearm swiveling freely without any end stops over the record from beginning to end.

Good luck,
In theory you can install an arm anywhere on the P2S arc and in any orientation as long as it can track the record. The manufacturer's recommended mounting distance for the 801 is 225mm. The figures 199 and 105 are just the sides of a triangle giving 225.

But mounting is turntable dependent.

Some considerations re possible locations might include if the arm will foul some part of the deck when it moves, or if it is awkward to use in a particular orientation, or if the cartridge is affected by approaching the motor, or if any suspension is adversely affected, or if the antiskate mechanism is compromised, or even if it looks a bit weird, or...

Specs on the arm at VE here.

thanks John, everything is clear now.
Hi John, What about us? The most are right-handed so the
'normal' arm position is already determined by the TT
producers. Or should I say plinth producers? I have seldom
seen plinths with sufficient space for a tonearm on the
left side of the plinth.
So Jorsan if you are left-handed you are in trouble. That
is to say you need to order a special plinth by Vetterone
and those ain't cheap.
Lefthanders are more intelligent so they just adapt and improvise.
Hi Schubert (the family of?), You mean that the super
intelligent lefthanders adapt and improvise on the
right side of the plinth. There is namely no left side
to adapt to or improvise with. Except of course when the
plinth is turned around with the cover on the front side.
no problem with that ...thanks god!
Hi Nikola
Lefthanders can always try switching the arm fingerlift to the other side of the headshell making it easier to use an arm mounted on the right hand side of the deck. (Always assuming the fingerlift is detachable).

I've being standing a bit to the right for over 60 years using my left-hand, never occurred to me I had a problem.
Hi Schubert, This is called 'assimilation' (aka 'the majority rule') while you actually confirm that the rule works. In 'good old days' the kids were forced to behave
'normal' and use their right hand. At present, in particular in Holland nobody knows anymore what 'normal' means. So even two lefthanders of the same gender are
allowed to marry . With each other that is.

Hi John, I already thought that your are a genius but because of my envious character I reduced your genius to the tonearms only. As far as I know nobody ever thought about even the possibilty of an headshell with the fingerlift on both sides. I also thought that you are Englishman and not a Dutchman.You should check your ancestors.
Nandric, you know the old joke,"In Holland you may have two daddies, but the dishes still have to be done right after dinner" .
Hi Schubert, Because of my ,say, Balkan jokes the
Dutch never invited me for a dinner so I don't needed
to do the dishes. And then I am sure that I have just
one dad but if I could do without him I would prefer
this state of affairs if this was possible.But alas my
mom was not the holy kind of a person.