I have an Omer Mimetic Med 6.5mm and it is fine, I too have big legs and broad shoulders and it fits real good. The idea with single lined suits ie open cell is that they are stretchier as well as warmer.
I would advise against buying a steamer as they are not really suitable for spearing in.
they are fine for a couple of hours in warmer water but not for serious freediving.
Regarding high waist , I have a long john style and I have no problems with it.
One of the modifications I would make is to fit a Pissette or Bec de Canard.
This allows you to answer the call of nature without marinating yourself
Kanoko is good for wear areas like knees and arse.
I can't recommend the Omer highly enough, I know a lot of people like the Elios suits too though.
I would also recommend getting a little tube of the Picasso wetsuit glue when you buy your suit, if you are like me you will need it.
