The Winchester 92 is a brute strong action. If you find some very old (over 30 years) loading books, you'll find sections for old WCF cartridges intended for Winchester 92's. You can push pressures of those cartridges well into the magnum pressures, and back in the day it was done all the time. Those rifles were routinely re-barreled to .357 magnum, and .30 Carbine; which puts it in the 40,000psi range. At a minimum you can get .30 Carbine performance out of your .32-20, and people used to do it all the time back in the day. They don't do it these days because there aren't all that many .32-20 shooters out there anymore, and we have so many modern cartridges that can meet or exceed such performance quite easily. So loading manuals don't even cover the subject anymore.
Early in the smokeless era even factory ammunition in .32-20 was available in high pressure "rifle only" (and by that they meant Win 92) loads, and people used to deer hunt with these loads quite frequently. These loads produced over 1,800fps out of a 24" barrel 92. So 1,200-1,300 fps is a walk in the park for a .32-20
So what you're looking for is very doable. Find some old load data and work your loads up carefully. Back in the day the preferred powder was 2400, but I'm betting you'll get as good or better performance out of 296/H110. Forget the "pressure signs" and use a chronograph. If you're pushing a 115 gr bullet over 1,700fps, you know you're comfortably into magnum pressures (assuming you're using sensible powders).