If you water drop them it will come WAY up though. WW alloy is well suited to heat treatment- even redneck heat treatment.
I haven't used that mix, but I got 26 bhn from just water dropping WW lead, and 18-20 bhn water dropping 1 part WW to 2 parts plumbing lead, so if you water drop, I would guess that mix would get you at least over 20 which gets you into the 20K psi charge range. 44 special tops out in the 15,500 psi range and 44 mag in the 40,000 psi range. So there is a LOT of variation between these loads.
Bhn of 11 would be fine for 15,500psi in a 44sp, but per Lee, 44 mag should be more like the range of 31.4 bhn. HUGE difference.
If it were me, and I didn't want to shell out for a tester, I'd use a mix backed by data double verified off the net and go a little heavier on the WW's. I'd lean towards a water dropped process so that the alloying goes further, but that depends on your source of lead. I have a large source of plumbing lead, and have to pay for WW, so I water drop my own mix to get the hardness I need with more plumbing lead.
Keep in mind, too soft means the charge pressure overcomes the tensile strength of the boolit, and when it blows past it, it causes "gas cutting" which leads up the barrel. Too hard can do the same if the boolit doesn't take the shape of the bore and the lube blows out. The lube basically acts as a liquid piston ring to prevent gas blowby, and thus prevents gas cutting.
But the range of OK is pretty wide. Since you won't know your bhn, I'd water drop to get it higher than 11ish to keep you in the safe range for preventing leading. And oven heat treating and a bhn tester are in your future if you want to push 44mag pressures.
But it CAN be done.
PS when I say oven heat treating, I mean a cheap toaster oven with a decent oven thermometer and a bucket of water
Like think less than $50. And one last note: If the hardness is not adequate, leading likely will take place pretty quickly, so watch out.