I'm well aware of the need to fill the case and have Cream-O-Wheat to top off light loads to keep a full case. The plan is to find an accurate charge for my 200-grain bullets.
I'm a Mike Venturino fan and read his book: Shooting Sixguns of the Old West. He emphasizes how the .45 Colt can sometimes be too much of a good thing! I plan to start in the 25- to 30-grain range for charges and fill the rest of the space with delicious Cream-O-Wheat for safety.
It should be fun!
By the way, I urge caution with those nail gun blanks. Those things are fairly "hot" and could boost pressures in a cartridge. There used to be a video on YouTube of some guys that tried them in a .22 rifle with airgun pellets as projectiles. I think the velocities were rather high, to say the least.
Stay safe, and keep your powder dry!
Dirty Bob