I have a favorite saying when it comes to bullet sizes, "a .22 will kill just as dead as .45, one's just more likely to do the job." Personally, I believe that it boils down to marksmanship training. And for a woman that's only 5'0", I'm more than happy to have her shoot the 9x18 (although she handles a .45 ACP rather well, but the frames are generally too large for her).
On the other note, yeah the surplus stuff is cheap and easy to find. I just like making my own stuff. It's fun. Hornady does make a nice 93 gr hollow point for the 9x18, and I think I will start with it for defensive rounds, but you can't beat the price of the surplus stuff for practicing with.
I shan't argue either point - but the larger rounds have more "fudge factor" than the smaller ones. Also, with a smaller round, you have to depend more on a directly lethal shot, which means you were "shooting to kill." With the larger rounds, you are "shooting to stop" - killing is incidental.
Also, defending shootings using handloads in court can be a cast-iron bitch - it's therefore not generally recommended to roll your own defensive rounds (a liberal lawyer can come up with "You've made the rounds more lethal" - whether you've done so or not - and try to paint you as a "mad dog killer." Stupid, but it's what we're stuck with.)
My wife can handle my 1991 rather well, and she's all of 5'2". She actually prefers my M1991 over her issue M29 (fortunately, I don't care either way.) The M29 grip fits her a bit better, but the M1991 is easier to handle and shoot, and second shots for her can be faster (since recoil energy gets used up in cycling the action, where you take it all in the wrist with the M29.)
(I've got bloody great paws with short stubby fingers, she's got small hands with long, strong fingers. That's why I can shoot a 12 gage one-handed like a pistol, and she can't control it without two hands. Understandable limitation, she just doesn't have the sort of forearm strength that I do.)
I could see rolling HP rounds for the Mak for soft-skinned varmint control, but I'd be loath to use them for goblin control - better to use factory ammo. Double-tap, and follow up PRN.