I bought a M91ED for my M75-6s cart and proceeded to do the same again for another M75-6S I aquired . Fit perfectly and play beautifully -if thats any help !!
I am not familiar with your tt , but my advice is to get the table upside down and get the bottom off . Check the platter wont fall off and damage anything and the arms secure (remove headshell if thats easily done maybe )
Take a picture of the resistive pots on the board (there are 5 you say...
In the scheme of things - I consider the relationship between the idling platter slowdown time ,and the time to slow down with a stylus in contact completely irrelevent ,surely?
5 turntables - 2 Aiwa AP 2200 's , bought in the last 12 months - I love emm DD drive ,semi auto , and built to last , one Ferguson belt drive , one HMV dd , and a Pioneer PLA -35