"I could never see the logic in going beyond standard loads in any gun when handloading. In contrast to hot loading, it would seem to be logical (less wear and tear on the gun, brass, and shooter not to mention more tolerable recoil), to start with the "suggested starting loads" in the manuals and then progress to small incremental increases in powder until a "sweet spot", accuracy wise is obtained while never going above listed maximums...just as the handloading manuals state. If one has a .45 Colt and finds the performance of standard loads unacceptable, it would seem logical to buy a .454 Casull.
But then, that just might make too much sense."
No, not really. First off, I believe the New Vaquero uses the same basic frame as the original .44 Magnum and .45 LC. That gun was considered strong enough for the full power .44 Mag. but recoil could get a tad uncomfortable. The .45LC could also handle .44 Mag. level loads should one wish to do so. I never loaded mine (I have both) due to the discomfort but they did handle heavy load quite well.
Then Ruger dropped the standard Blackhawk for the much heavier New Model Blackhawks which were stronger and handled recoil much better. There were some old model super Blackhawks prior to the new model which also were better. I have samples of those as well.
FRankly, and this is just my not very humble opinion, what I would do with a new model vaquero is work up a load similar to Skeeter Skelton's pet load for the .44 Spl. which is safe even in the Colt single action and clones. In the ,44, 7.5 gr. of Unique for about 950 FPS, give or take. Some take it a hair higher but that's where I quite. Do the same for the .45 LC and enjoy. It might take maybe 8.5 gr. with a 250/255 gr. cast bullet but it would be powerful enough for just about any use you might think of including hunting.
If you want more spit & git go to the full size New Model Super Blackhawk.
Gun writer Ross Seyfried once recommended a Ruger Bisley 5.5" barrel as a very useful all round heavy game gun in .45 LC. It handles .44 Magnum level loads with ease and is built like a tank. Weighs about as much as one too.
So to the OP, my suggestions would be to work up a load in the 950 to 1000 range. Use a good 250/250 cast lead bullet and enjoy life. For the record, I live fairly close to a mountain range that has Black Bear and Mountain Lions. Some of the hiking trails are quite popular with the college crowd and when I hike thee, either an S&W .44 Spl. with Skeeter's load, or a 4.5" Ruger Super Blackhawk with full power Mag. loads is usually with me. When I pack the .45 Ruger Bisley, it's in a shoulder rig and is loaded to the max. Frankly, I would be just as well armed with a Colt single action and a Skeeter Skelton lever handload. Easy on me and easy on the gun. Your choice.
Regarding, "But then, that just might make too much sense."
Not to me, but then I've been doing the handgun scene since 1954. I had to kill a Black Bear with a hot loaded .38 Spl. in 1959 to near .357 mag. specs. Guess we'll just have to agree to disagree.
Paul B.