i use the salopettes and that sees to me bottom half but not like some anglers,i dont fish at night because of bad health,good boots are essential as are decent pair of gloves .high viz waterproof jacket and fleece lets me move about and doesnt hold iz back when im casting.thermals are ok if ya like um but i prefer to wear baggy clothes.
all in one and 2 piece suits are highly recomended but as with all my winter gear i dont put it all on till i get to where im fishing to much sweating on the way to the mark will leave you cold all night as soon as you stop moving ,i find it better to put on as you feel colder then i feel the benifit of the winter gear.
id go for an upper priced flotation suit ,heard to many bad remarks about the cheaper ones and some of the dearer ones are way out of my price bracket for what fishing i do.