The potential continuous draw figure drops as, in a hard battle, you could have a few startups and a stall or two's worth in amps to get out of that maximum 44a average draw figure. If you can get more than 2.2ah, I would.

Also, is it right that C rating doubles by putting two packs in series? That doesn't feel like it should be the case? Are you certain that is actually how the math works? If not, you have a maximum of 88a continuous from those packs. At 12s the 750MX can pull beyond 160a. Looking at your battery link I see no mention at all of burst C rating. If the burst isn't great, and the C rating doesn't double when you series the batteries, you could potentially be beyond the power of the batteries in both discharge and capacity.

Someone with the knowledge, I can see how discharge would double if you parallel two packs, but not quite how that would work if they're in series... enlightenment please!