RE: How many grains?
Mike I used to shoot a lot of maxi ball and they do an excellent job on deer. Out of my Hawkins and Renegade they were real accurate. Then I started shooting REAL conicals that I cast at home. I use a homemade lube on them and they are not only very accurate but just knock the snot out of a deer when you hit one. I shoot them out of Renegades, Hawkins, and other 1:48 twist rifles.
I also got a great deal on some Buffalo Ball-et and have to admit they sure load nice and shoot good out of my .50 T/C Hawkins Flinter. A real kicker is I bought some 405 grain Ball-ets for my .58 caliber Renegade with a GMB 1:70 twist and they are super accurate.
The last batch of maxiballs I bought were home cast. And the person must have been tired that day. One will fall down the barrel and the next one you need a hammer and a wooden dowel to seat it.... Just no consistancy with them. So their accuracy is hard to judge.
Actually, people are always looking for a better projectile. I guess that is what lead me down the inline path. The trouble is I keep coming back to plain old patched roundball. Still on a whitetail they are hard to beat when you place them right. Although the fancy rifles do a good job too...
If they work for you Mike and they load nice, then use them. It is always nice to have a number of different projectiles that you can shoot..... Would sure make a nice fast second shot since you do not have to patch them.