Well, I have a 10' Oliver disc that I use with my 1650D in fairly light soil.
It seems to me to be plenty of drag: not because of pure power but because in plowed or otherwise tilled soil in my vegetable operation there's enough resistance that I lose traction rather easily. I have two sets of wheel weights but fairly narrow tires: 15.5 -38,
I have a friend with a 1265 and I don't think his tractor has any more traction than mine.
If you have other choices for discs, I'd consider something smaller. If not, you can probably make it work.