Yep, 15mm servos are a buggers. 20mm wide ones are easy to get in brushless with strong torque for a reasonable cost.
12mm & 13mm are easier to find too.
I don't think Hitec makes a 15mm and Futaba only has one model with 15mm wide.
I never had a JR servo, and I'm not sure the new JR is the same as the original JR.
I wish I could feel positive with Savox, but my experience with their small models has not been good.

I think I'll stick with MKS 747 & 747R or Promodeler 355's.