Same here, but if I know I'll want to make a BIG print, I'll bring along my 4x5 -- if the situation can accommodate it. But because, like you, I'll probably have to rely on my Minolta MGs or Minox IIIs in many situations, with Agfapan 25, I can still make bug prints, like 16x20", if I'm careful.
All things considered, if I enlarged an 8x11mm negative and a 4x5" negative to four or six feet, of course the 4x5" would win, but the smaller negative would "put up a good fight".