Hiya
Now to confuse you even some more!!
After about a years hard diving, your 5mm wetsuit will have compressed and will most likely be closer to a 3mm wetsuit!!!! You'll notice this when you buy a new wetsuit. You'll need more weights to counter-act the additional bouyancy your new wetsuit has compared to your now old compressed wetsuit.
If you're going to be diving alot, in quite cold water, i'd look at a cheap open cell wetsuit, so that you can replace it during the next year or two. My old 5mm, which have compressed to about 3mm's by now, is used when i go on holiday, in warm tropical waters.
The short life span of an opencell wetsuit is one of the dis-advantages.
Regarding the whole vest issue, how will you know when to put your vest on?? You can get very warm water in summer or very cold water. You'll have to decide BEFORE you enter the water. Gonna be a real pain if you find its too cold, then you have to get out and put the vest on. Or vice versa, too warm with the vest on and you start overheating.
Stick with the farmer john/long john bottom and seperate top. You only choice now would be 5mm or 6.5mm. Dependant on how cold water you are prepared to brave!!
Regards
miles
