When I purchased my Redhawk in 44 back in the mid 80's I got it specifically to trade for a 41 if I ever found one. This said, I ended up mounting a Leupold 4X on to of it and started working on hunting with it. When I found the 41 I traded off my BH instead.
Anyway, as with quite a few loads I have worked up in the past, I looked through all my manuals, and called a couple of the bullet manufactures to get their opinion and test results with different bullets. I as concerned with downrange energy and expansion and it just seemed logical.
I had two manuals from which I was actually using to work up the loads, one the Lyman 46th edition and the other Sierra. I can honestly say that the top listed 180gr load in the Lyman manual, is about as much as I wanted, and it shot consistently 2" or less at 100yds, from a rest similar to the one pictured. The concussion from this load will knock dirt loose from the rafters, but it shoots.
Along this same theme, I have also worked the 200 and 240gr bullets up to similar performance levels for their perspective weights. All have been easily as accurate as the 180's or as tight as I could hold them depending upon the rest I had at the time.
I was heading to WI for a handgun only hunt one year and working up loads with the 240gr XTP and 296. I had my loading gear at the range and was tweaking up the powder ever so slightly looking for an accurate top end load. What I found was I ran out of room in the case before I started to flatten out primers, and the velocity actually fell off when I got there. I was using two different primers and there was little difference in results between the two. I have for the most part always used the Win-WLP's but in this case I had also tried some Fed Mag as well.
I guess the bottom line is I have been to the top, but nowadays I am back to the middle with 99% of my loads. I have since found with the 41, that I don't need the full bore flame throwers to get the job done in the areas I hunt. Out to 100yds and further the 41 loaded with a 200gr Rem JHP to around 1300fps, shoots flatter than you would ever imagine, and will roll a 200# feral hog on it's ear. Like the 41, the 44 loaded with a 240gr to around the same velocity or so will easily do the same or more.
Like you, if I want more than I can get with those I have the 454 to roll with, and no need in pushing the others to their limits anymore.