yep. I've been agreeing with you the whole time, just adding a little more information based on my experiences any making a little fun of myself there.
I talked to him a few weeks back, helping him get back on the road after a bent 105 sector shaft. He can tell that story if he wants
I don't run hydro assist on my 80, but I have on 6-7 of the other toyota crawlers I have built over the years and have put hydro assist on many friends/customers rigs. I know the 80 pump flow, pressure, its limitations and where the shortcoming are in the 80 system. If I did put hydro assist on my 80, it would not be comparable to these since the tie rod is in front and the steering arms are about 2" shorter than the 80 rear tie rod setup. Different ram speed and different leverage, I would need a 6.75" stroke ram and closer to a 1.75" ram to equal the speed an force of your setup.
I have twisted sector shaft splines with hydro assist and been on runs 2x when others toy sector shafts have snapped. That was running 40's, but on a cut up 4runner that weighed about half as much as an 80. All on mini truck boxes, but those have the same shaft diameter and spline count at the snappy part as the stock 80 sector shaft.
All I am saying is -
stock steering =not great.
+ 105 shaft + good cooler = stronger against breakage, same steering "power"
+ hydro assist + good cooler = stronger against breakage and increased steering "power"
+ hydro assist + good cooler + 105 shaft = strongest, increased power and more betterer
All of those assume you have a better than stock tie rod and drag link.
For slow speed crawling the ram takes a lot of load off of the sector shaft most of the time. If the front tires are bound up and you are cranking the wheel just as hard as you would have without hydro assist, the sector shaft is seeing the same load as it would without the ram, though you are Applying way more force at the wheel. The pump is putting out the same pressure as it did before the ram was added and that pressure is pushing on the piston in the box the same as it did before hydro assist. You just dont get into that situation as much with hydro assist, since you have much more force available to move boulders out of the way.
At higher speeds the stress that breaks stuff is much much more sudden and jarring. Especially if you run a front panhard with rubber bushings that deflect on big hits, your sector shaft is taking a huge hit each time since the drag link is solid and the panhard bushings deflect while you have a death grip on the steering wheel. That is where I worry more about breaking a sector shaft, since the consequences are much worse.