I just mounted a US Optics ST-10 on my M1A.. I used the Sadlak mount and US Optics extral low rings...The objective is only 37mm..
I still needed to add a 1.5" cheek rest to get an ok weld.. This will have to do until the JAE-100 shows up at the door
As far as the optics go... DO NOT buy a cheap mount or optics..
For the mount I would go with one of the big three... SEI, Sadlak, ARMS.. (I have the Sadlak and it is rock solid!)
For the optics I would also go with a big name (quality)
Leupold, Nightforce, US Optics... Tho the Super Sniper is a great scope you won't get the adjustable zoom...