Quick question: Why are so many people spending so much time shooting one-handed and, especially, weak-handed?
I'm not trying to argue against the practice, I'm really curious. I just can't imagine too many scenarios where that would be necessary.
One previous reply suggested that you spend some of that ammo budget on training. His suggestion is a good one -- for you or for anyone.
A lot of people shrug this off, saying, "I've been shooting all my life." In most cases this is a poor rationalization, because far too many of them have been shooting the wrong (inefficient) way, probably based on what they see in the movies or on TV.
There are excellent classes available to almost anyone. I'm not referring to a concealed handgun class, or to a two hour lesson, but rather to a two day or three day "immersion level" defensive handgun class. In virtually every case, assuming you avail yourself of the training offered by one of the top-tier instructors, you will understand how little you knew prior to the class -- and how much you still have to learn.
A poor analogy is the situation when someone gets his first pair of glasses, and suddenly realizes how poorly he was able to see before getting the corrective lenses.
After taking such a class, you won't ask why you should learn to shoot one-handed, or why you need to be able to manipulate a flashlight while you shoot, or why you need to be able to shoot while moving, or why you need to be able to effectively engage multiple moving targets.
One more comment. In your OP you referred to wanting to "master your gun for SD and for fun." I would suggest leaving the "fun" part out of it if you are limited to 50 rounds per week. You have a massive chore in front of you, under the conditions you have described, just dealing with the "mastering for SD" part.
Practice is essentially simply a repetition of whatever techniques you are using. Keep in mind that if your technique is poor, or inefficient or ineffective, you are reinforcing bad habits.