Tonearms - SME 3012, Jelco, or Schick?

I owned an SME 3009, no experience with the long version or the other two.

Satisfied my long arm itch with a very long 12.5" effective arm from Russia. Unfortunately it has a fixed headshell, and the height adjustment is via set screws like the SME (mine made precise via micrometer provided). Your 3 choices all use the set screw method, not ideal for sure.

After changing from a single to a setup with 3 tonearms, the arm I like most is a removable headshell for alternate pre-mounted cartridges (including friends cartridges played here), combined with arm height/VTA refinement while playing (loosen/up or dn/lock by hand, no tools required).

505L on eBay

I suggest you have a good look at Micro Seiki 505L, which is a compromise effective length of 11-1/8", with superb adjustment features, VTA while playing, and it’s headshell fitting allows Azimuth adjustment.

I installed two 505’s on a wonderful Luxman PD-444 TT for a friend, learned what to ask about/avoid, if you look for one, write me a private message.

btw, think long: have you considered the potential of two arms? If you listen to Jazz, there are so many wonderful Mono LPs, it is wonderful having the advantage of a true Mono Cartridge ready to go.

The Luxman PD-444 appears simple, but it contains great technology from head to toe (if you have the extra width it needs). 

Screen Shots from Luxman PD-444 Manual

I didn't have the width, so I went with the deeper JVC PL-2 Plinth

what other long arms have removable headshells and easy height adjustment?

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.