ORIGINAL: 2slow2matter
You need a different prop anyway. I use 14 X 8 or 15 X 6 on all of my saito 100's. The 14 X 6 is perfect for the .91, but you need more prop on that 100 to keep it from unloading too much in the air.
Having said that, it won't help your spinner situation. The MAS blades are probably thinner at the root, so they may fit the spinner with less modification.
Looks like I am 0 for 2, wrong spinner and prop!
I want to thank you guys for your help. If I decided to stay with the APC prop I will have to buy an aluminum spinner (the kind you tighten with a screw driver?) or buy a master air screw prop? What are the pros and cons to each option?