Have seen these with an 18 & a 20" reflector.
NGC 4169:"Brightest of three (NGC-4174 & 4175). Center is bright and solid. Harder to see full extension."
NGC 4174:"Fainter and oval in shape. Seen with NGC-4175 and 4169."
NGC 4175:"Seen with NGC-4174 & 4179. Dimmest of the three. Not quite round."
NGC 4173:"Transparency dropped but could still make it out, averted vision #3. Adjacent to a star to make it easier to find. PA ~ 160 [134]; " NGC-4173 is the largest of 3 galaxies; elongated, faded to edges."