That's a very cool solution. Creative engineering! I built a hidden winch mount for my 5th gen 4R from scratch with no plans because it was new and there weren't aftermarket options yet. It has similar frame horns (probably lighter gauge metal?) so I made a plate type bracket that ties back to the side of the frame rail like many aftermarket ones do now. When I'm fabbing in sheet metal I tend to force everything into my procrustean bed of being some version of cut and formed steel sheet rather than thinking more broadly about other designs. This solution is better in its simplicity. Love seeing this kind of stuff.
Agreed this is a great way to reinforce the horns. Got any pics of the plate type reinforcement brackets?
I likewise have a home brewed HWM. It probably doesn't put even a 1/4 of the stress larger bumpers do. The cyclic stress is probably what kills these frame horns rather than recovery related forces. Though that begs the question to know when the horn is compromised and a recovery load shouldn't be put through these bumpers/horns. For that reason, I think the factory lower tie down/recovery points are still key to use in a recovery, maybe with a snatch block, to better distribute forces.