Tonearms - SME 3012, Jelco, or Schick?

Thanks for all the information!  Very helpful indeed.  I will look at all the recommendations.

Cartirdges - It will be a moving coil, most likely a Umami Blue or ML, possibly a Dyanvector DV-20X2L or a DRT-XV-1s.  No SPU's although having one intrigues me.   My TT can support 4 arms, what is on there now is a Micro Seiki CF-1 with a AT VM760SLC and a Grado Arm with a Sonata 2 cartridge.  So all of this is a setup in performance.  I'd rather put the money into a cartridge than in the Tonearm, although I suppose I can buy a lesser cartridge and a better tonearm.

BTW, I only have a few mono records.  These are from Mom's estate, so mostly big band, 1930's to 1950's jazz.  Some are in very good shape, some are not.  I thought about a mono cartridge but for the few albums I have, it doesn't make much sense to invest that money into a mono cart.

I have an SME that I liked with a Benz Glider, but prefer the Jelco 850L if you find one, especially with the adjustable VTA for it. Using it with a Benz Ruby H, and have been happy for several year..

If you can be lucky enough to find a Jelco TK-850L, jump on it.  It was the last generation Jelco and is quite good.  Earlier Jelcos are lesser performers, but the better ones are OK.

A caution on the MS 505 arms for anyone considering one.  I agree they can provide very good and convenient performance, but one thing to watch for.

When I got mine the stub beyond the pivot point where the counterweight mounts was not in the same plane as the arm tube itself.  A search online was not helpful as some reported that was normal.  Some online photos even showed the droop.

So I sent the arm to a trusted repair service (sadly no longer available) who confirmed it was not uncommon but not normal.  They were able to repair it so the  stub is now on the same plane as the arm tube.