OK.
Some time ago I made electronics for my EQ3, it fitted inside DEC compartment next to counterweight shaft, see attached image.
I am still missing timing pulleys
(1:4, with 48, 12 teeth or some other suitable combination) for T2 belt (which I have) transmission, so I will simply print them with 3D printer, this should be OK for wide fields. Hopefully the larger one will fit to your mount, and you will be able to fix the motor with suitable bracket.
If your mount has 144 teeth worm, I do not have to change firmware for Motorola processor used here.
It is certainly possible to do the same thing with one of small Arduino or digispark processors (plus stepper driver board), but this is almost ready and tested, so....