30" span Ringmaster Junior with 200 sq. in. wing area would work with the OS Max 10 CL on 42 feet lines. Brodak has a kit:
http://brodak.com/jr-ringmaster-kit.html OS 10LA is more comparable to the later legacy cross scavenge 15's of the 1960's, more power than the OS Max 10 cross scavenge. A review of the RC version of the 1966 OS Max 10 is here:
http://www.sceptreflight.net/Model%2...281966%29.html
I've got 2 of those RC versions, great sport engine and good hop up for an 049 reed valve RC, weighs only 3 oz w/o muffler. Broken in a 7x5 prop would probably be the right ticket for CL.