My experience is with 44 Colt.
21 grains of FF fit nicely in this cartridge with little compression, seating the MAV big-lube bullet.
These are for my Open-top & 1860 R-Ms. Light-weight revolvers for sure.... In which I typically shoot 44 Russian for CAS.
The 44 Colt loads gave noticeably more recoil than the Russian, but still easy to handle.
Since 44 Spl. is longer, I'd guess you'd be using around 25 grains, maybe more if you like compression in your rounds.
Have to say one thing...I've used 2F, 3F, & even 4F in many cartridges.....and can say I greatly prefer the use of 2F in all revolver cartridges & shotgun (cartridge or front-stuffer). This includes 38 S&W, 38 SPL, 44 Russian & Colt, 44-40, 45CS, 45-70, 12 ga, etc. IMO, 2F (FF) measures & meters better, fouling is a bit softer. Velocity is not quite on par with 3F, so use 3F maybe in hunting loads. Fill to the top of the bullet, or more, - ifn' ya need a bit more punch!
Good rating for "flames" too.
For everyday use, I choose FF.
Oh, I also shoot a lot of C&B...I prefer 3F for this.
Regards,
Slim