My Colt 2nd generation 1851 Navy takes a maximum of 27 grains of Goex FFFG with a .380 inch diameter ball weighing about 90 grains. That's without a felt wad.
This is as much as I can get into the Colt.
My two Remington .36s, one made by Pietta and the other by Uberti, each max out on about 30 grains.
In my Colt 1851 I typically use 22 to 24 grains of Goex FFFG black powder, with lubricated wad and .380 inch ball. This is also a good load in the Remingtons.
The lightest I'll go is 20 grains, which I use for target shooting.
The Remingtons have fairly short rammers, so any less than 20 grains and I can't be assured that I'm shoving the ball down far enough to be snug against the powder. This is with a lubricated felt wad, too.
In my shooting kit I have a little plug of 5/16" hardwood dowel that I can put on top of the ball and use the rammer against. This ensures that the rammer will apply enough pressure to seat the ball firmly on the powder.
Leaving a space between ball and powder creates a dangerous condition that can raise pressures considerably.
In my 1862 Colt made by Pietta, I use a maximum of 18 grains. Its chambers have much less capacity than the Navy, because it's built on the 1849 frame made for .31 caliber.
I haven't found a conical bullet as accurate as the ball in my .36 revolvers. I've tried a number of different ones, including the Lee of both .375 and .380 diameter, and the Buffalo Bullet.
The .44-caliber Lee bullet is accurate in my .44s, but for some reason not nearly so in my .36s. It would be interesting if Lee made a .31 conical based on the same design, to see whether the caliber or design may be the problem in the smaller calibers.
I generally avoid loading conical bullets; not as accurate, slower to load, more expensive to buy (if you don't cast your own) and generally more bother. Velocity is lower too, because you must use less powder to make room for the conical bullet's greater volume in the chamber.
I like the .36 caliber. I wish someone would produce a stainless steel target .36 of Remington design, with modern sights and fairly deep rifling with gain twist. It would be a great shooter and small game gun.
I have an Uberti-made Remington target revolver in .36 caliber, made in 1973, but the rifling is so shallow that it's not nearly as accurate as my stock Uberti-made Remington .44 revolver.
I'd be tempted to rebarrel the Remington .36 target model, but it's a fairly rare bird so I'm keeping it original. There are plenty of Remington .44s with modern, target sights, but you very rarely see a .36-caliber of such configuration.
So yeah ... start with 22 grains of FFFG with a .380" diameter ball and felt wad twixt powder and ball. See how that works for you.
"And lo, did I see an ugly cat. Smoke. Brimstone. Holes in parchment. And this ugly cat was much amused." --- The Prophesies of Gatodamus (1503 - 1566)