Here we go again.
The best load for your gun is the one you determine for yourself by trying out several options. The manufacturer's/distributor's/retailer's recommendations are worth exactly what they cost you.
Start with a mild, even low load, say 20 gr in a .44 Rem NMA. Use grease or wads or corn meal or whatever, at this point it's not important. Load each chamber the same way and use the same amount of compression. Shoot 3-5 rounds at 7-10 yards ALWAYS using the same POA. The point is to shoot groups, not hit the bull.
Reload using 22 or 23 gr, the same wads/grease/meal and use the same amount of compression, shoot 3-5 rounds at the same distance. Repeat with 25 gr, then 27-28 gr, 30 gr, 32-33 gr and 35 gr. It should become clear which load shoots the smallest groups. I doubt very much you'll have to go much above 30 gr as the group should open pretty quickly with those heavy loads.
Once you've found the best powder load you can then experiment the same way with wads/grease/corn meal options to see how those work for you in your gun.
Now if you want you can start adjusting the sights in any manner you wish to shoot accurate POA's at longer ranges.
This should result in the most accurate load for your gun. I think it will be about 25 gr, give or take a bit. But maybe not.
Or you can just fill up the chambers and blast away,