I bought mine just because I could and for once I wanted something new. Still reckon it is a lot of bang for the buck. Most of the problems I had were niggily little ones that the idiots at the dealers who supposedly gave it a PD check either did not pick up on or were just too lazy to fix. Yep, a ribbed belt will mean new pulleys and I have my eyes open looking for scrap I can make them from because A: I'm cheap, B: I'm always broke. The reason I'll go for a ribbed belt is one belt, easy adjustment and they are quiet, quality matched belts arn't cheap and I want to route away from the change gears for a future mod. Something to think about with link belts is they directional and reverse on your lathe reverses the motor.
For now at the stage you are could I make a suggestion? If it were me I'd remove the mount, clean up the adjustment slots and align the motor to the mount,(something I had to do), replace the mounting bolts with 12-point head ones to make using a ring spanner easier and use it while taking time to design a new motor mount. I agree a hinge would be far simpler and easier to adjust but I'm waiting until I get around to changing the belt. Have a look under a car bonnet at the alternator/ power steering/ air conditioning belts and how the adjusters work.
I look forward to see what you come up with.
That is basically the design I am going with. My older lathe has it also and I just changed the alternator last month
The belts you are considering is a wider belt? I am OK with changing out the double belt idea. As I recall, double percis sion belts from gates are not exactly affordable. I know that from my rockwell lathe.
As for all the stuff, I don't mind, just wish I knew where all the shortcuts were made so I can chase them down. Bolts, they aren't that much money... the head alignment cap screws not being tightened and locked on... that's a bit much. Missing bolts holding the lathe to the cast iron base... hmm mm, cross threaded bolts. Missing handles for the gearing controls, yea... misaligned bolts for the gear cover...