I suggest a used copy from Amazon Lyman Black Powder Handbook.
There are ffffG published loads with velocities
and pressures listed for 4 replica Colts:
1) Brand not named replica 31 cal. Colt Baby Dragoon 5-1/2" bbl
2) Lyman replica 36 cal. 1851 Navy 7-1/2" bbl
3) Lyman replica 44 cal 1860 Army 8" bbl
4) Ruger Old Army 45 cal 7-1/2" bbl
They list maximum loads and lesser loads.
They list loads for different projectiles
They list loads for different brands of black powder (some are old brands, the book is 1975).
Loads in fffG and different loads in ffffG for every table.
I'm just a guy on the Internet. Suggest seeing it in print from Lyman.
Here is the exact book edition, can buy used for $10 including shipping right now.
https://www.amazon.com/Powder-Handbook-Kenneth-Ramage-editor/dp/0912412070/