What are the differences between CM-2 & MR-10 (Abrasion Resistant) and Thermoclear/Twin-wall then? Or would that be a question that would be better directed at the company?
Thanks.
Your vendor knows best, but from what I've found online,
Tuffak CM-2: abrasion resistant coating
Lexan MR-10: abrasion resistant coating / UV resistant coating
Lexan XL-10: UV resistant coating
Twinwall: Don't use. It has two walls (really?

) with spacer spines at intervals which gives an airspace between the walls. It's used for greenhouses, signs and displays. Not good for CP covers.
You might also encounter Makrolon which, like Lexan or Tuffak is another brand of polycarbonate.
Go with the scratch resistant before the UV resistant. Between the CM-2 and the MR-10: get whatever is less expensive.