What tonearm will better mine?

Hi Noromance

You should try a "WOODY" From Pete Riggle. I have had a system very similar to yours and my 401/Woody/SPU  really made music in that combination.

A tone arm can be a weak link.   Your's is not!   The Decca is an excellent, but very finicky cartridge!   If its working well?  That means your arm has to be excellent.  Leave it alone.   I have destroyed Deccas not using a tonearm that will work with a Decca. 

Deccas I love.   They eliminate the obscuring of the signal that using rubber for the regular cantilever's bushing. The tonearm has to be exceptional to work well with a Decca. If you are looking for a way to improve  it may be a different tonearm cable.  But, if the Decca works fine?  It means the arm is excellent! 

I recently bought two Jelcos (SA-750D and SA-750E) for my modded Empire and Lenco tables.  The one on the Lenco replaced a JMW 10.5i arm and spare armtubes and sounds better to me in ALL respects.  I came out of that deal with more than $1K in cash, so hard to complain :-)

And yes, I'm running a Decca Super Gold too (among 9 mounted carts) and the Jelco loves it.

PS  The SA-750D is a direct drop-in replacement for the original Empire arm (Model 298) and an amazing improvement.

I’ve had many Deccas over the years in various arms. I think "boazro1" has it right with the Graham arm. I’m sure they have an an arm wand that will have the correct weight for the cartridge. The arm, as I recall, has variable damping that can be a boon for Deccas. The SME V has this feature too and I have heard such a set up with a Decca that was magical. ( The dealer should make sure the cartridge - any cartridge -has the correct azimuth before selling it to you.) Also, I understand that the Deccas need to be loaded differently (Ohms) than conventional 47KOhms so you may want to get that correct before trying new tonearm cables. I always find I like to do upgrades incrementally it increases enjoyment over the long term.
I have used several series 9 Ikeda (of Fidelity Research fame) cartridges that are a "moving coil Decca" with wonderful results. Unfortunately, the new Ikeda company will no longer be offering them. However, their new tonearms are supposed to be an update of the (rare) FR -64 and I have no reason to doubt that.