In MMOs, I do equate minmaxers as twinks, at least in low-levels. However, in MUs, I tend to just call minmaxers as minmaxers.
Twinks in a MU environment, IMHO, are almost always those who do something so completely OOC, like singlehandedly try to take over a space station or other things that ICly aren't plausible without some heavy skill usage and/or social engineering. They don't play by the established rules simply because they don't feel they need to, and want to prove they're badass.
But I may just have picked up that style of the terminology from a few admin I knew from my first MUs, and held it, even if it's not a 100% valid definition. 
