This observation of NGC 4536 with my 24" was made at my local observing site on a better than average night (SQM-L = 21.5):
Bright, very large, very elongated at least 3:1 NW-SE with two long...
I can contribute a 16" drawing of NGC 4536 from 2009 (196x, 23' field). I didn't find the spiral structure to be difficult in the 16" scope. I'm sure it can be seen with smaller apertures as well....