The simplest thing to do with any GL75 is throw the tonearm away, mount the deck in a heavy solid plinth and drop a Linn Mount and geometry tonearm in.
Once the GL75 arm is removed you see a hole on the plinth of about 48mm diameter. The hole isn’t completely round so you have to take to the back of the hole to make it completely round but it only takes a few mins with a half round metal file. Offer up the Linn type arm collar and mark out the bolt holes, remove and then drill 3 holes in the plate. Mount the collar with the bolts and drop the arm in.
A Linn arm wants to be at 211mm spindle to pivot really but the GL75 arm is 210mm I think so there is a small degree of geometry compromise. You’ll find the cartridge once aligned, to say Baerwald, will sit ever so slightly askew in the headshell. It isn’t a problem in practice though.
Suitable and cheap arms are obviously Linn tonearms themselves or Linn pattern Jelco’s and their derivatives. I personally liked the Jelco’s a lot in this application. The Jelco SA-750D is perfect for the job but things like the SA-250ST ( and the Mission 774LC derivative) are cheaper alternatives. Avoid the SA-370H (and the Sumiko MMT, LAD and Nakamichi variants) though as they may have Linn mount arm collars but they need a different mounting distance (222mm).
I did one like this for a friend using a Russ Collinson plinth, a lick of paint and a Jelco 750D and it was positively singing with a Benz Ruby 2 and AT33EV on it.
Simple and effective way of getting much much more out of a Lenco 75.
(the SPU was just for show as you can’t achieve correct geometry since overhang is fixed)