I hope that the 50lb mono over tests. You're a bolder man than I am fishing 40% @ strike (full disclosure, at the most I'm a 1/3 @ strike an 1/2 @ full kinda guy).
If you want to fish the HX at 20lb strike, the 760M would work just fine. I fish a 760M as a heavy GOM chunking outfit using 80 to 100lb topshots and drag up to 33lbs. As a true 100lb rod it's a little light, but in my humble opinion, it's too strong for true 50lb (80 is the Goldilocks number for this blank).
The 765L could be a good blank for this application. Do you want to fish stand-up w/ a harness, straight rail, or harness and rail? If it is for stand-up, I'd stick w/ a 6ft blank.
If weight is a concern, OTI would be a great choice as their stuff is super light but super strong. On the other hand, if you're the kinda guy who uses his rod for a fish bat

, stick w/ a composite or e-glass blank from seeker or calstar.