Odd thread... on the trainer I don't wear a shirt. When I get hot I open the door and some windows.
The usual way to wear bibs is straps on the inside. Good straps won't shift around so much. Many bibs have short straps and I have Boure put a new top on them. Their straps are longer and wider.
The idea of wearing a baselayer below the straps is intriguing enough that I'll try it if Spring ever comes.
"Nice pressure on the abdominals"?? I thought the whole idea was to take pressure off the abs for comfort and better breathing. Your bibs may be too small...
My favorite synthetic fabric is Powerdry. You may have to poke around to find a t shirt made from it.
I have had good luck with Patagonia
http://www.patagonia.com/web/us/prod...IRTS#sku.21102