Maybe @Despos can answer it - I don't really have the technical knowledge to answer it properly but Ill give it a try:Very pleased to hear, what exactly in the back? I want to go to the tailor tomorrow but want to know what to ask for in particular.
1st suit pants look tight in the back, which causes the wrinkling
2nd suit looks tight in the back of pants and jacket which causes wrinkling/ backside of sleeves looks messy
3rd suit its mainly the backside of sleeves and pants that look messy