Hi inertia8
with the full suit - we find we wear only underpants and singlet/tshirt (and warm socks of course) underneath. Thats all you need
And we don't decide to put our suits on until it gets below about 7 or 8 degrees - if we do, the front is generally pretty much unzipped
Note - we rarely leave our suits at home when we go observing - depending on where you are, you can still get cold nites in summer
i have thought of trying the combination of the bib&brace and jacket myself - but resisted while i still fit into my full suit
i think if you were going to be inside/outside on a regular basis during your observation session, the two piece solution might be beneficial.
Of course the B&B and jacket would be better than just trouser and coat option. More protection around the kidney area when bending over.
Two piece options are also better suited to female application i would think
another consideration is that a one piece can be a little big and not suffer from "air leaks" so much.
hope this helps
geoff
