Pyro will compress a LOT. You can pretty much fill any chamber and the ball will just compress to fit... With Black Powder the ball will not fit if you do this because your loading rod will bend or break before you get the ball flush.
But I sure would NOT do this to any gun you like... I really wore out my Walker Uberti with large loads in a hurry. I ended up finding that 35gr of 3fff was the best load for it anyway.
I just checked and "my" 60gr volume measure threw a (scale measured weight) around 58gr of 3fff GoexBP and 44gr of Pyro "P".... I don't think you will want to feed your new pistol a steady diet of anything close to this. Also the loading rod will usually drop down after every shot if you use the "magnum" charges ... this alone is so ANNOYING that the lighter charges will be much more appealing after a few cylinders...LOL
Just an option...but a 45 Colt case holdes a volume of Black Powder that weighs around 40grs... so an empty 45colt case will work well as a measure and they are pretty easy to come by.
One of the scariest things I have ever seen or heard of, is the use of the wood dowel to seat caps!!!!
This is a total hazard thought up by the warning label generation! I did see a picture of a guy that about blew his thumb apart from thumb seating
All the old timers were taught and teach to "Hammer Seat" caps by cycling the action of the pistol and applying pressure with your palm or thumb to the hammer on every cap... this way if a cap does pop at least you have the gun held proper and the ball will go down the barrel...As long as you always have the muzzle pointed in a safe direction (which you should) there will be no problems... If a cap pops with the dowel method the ball will go down the side of the barrel (well, at least most of the ball) and most guys will be craddleing the revolver in there palm.
Hope this helps and Have Fun!!