I add about 8 oz. at a time to keep the pH from drifting too high. I bought a 5 gallon bucket on a Home Depot trip and keep it in the pump house with an 8 oz. disposable cup.
When I dose, I fill the bucket with pool water half-way, carefully pour out an 8 oz. cup of muriatic and pour it into the bucket. I dump the bucket in the deep end near a return. Haven't roasted my shoes or shirts yet. I figure that if I get a little splash, at least it's not full strength, it's bucket strength.

It's an extra step or two, but so far, so good.

Good luck, you've got painting clothes. Don't tell the wife!

Condo Steve