I don't want to use reloads for SD myself, but if you're justified in taking the shot, it shouldn't matter what ammo you're using, whether it's handloaded or not.
Although I don't reload at this time, I've often thought it would make sense to make up some ammo with similar characteristics of my SD ammo. That way, I could train with ammo like my carry ammo without the extreme cost.
I know of only two manufacturers that have decided to produce a practice ammo with similar firing characteristics to their SD ammo. Speer Gold for SD and Speer Lawman for training, and winchester produces SXZ training and a similarly titled personal defense variation that eludes me at this time, but you can find it at Bass Pro Shop. (I can't find it on Winchester's website, maybe they stopped production.)
While I wouldn't use handloads for SD, I wouln't object to using them as practice loads to save some cost.