Used a Kokotat full dry suit in 79 degrees/wind first time . The suit is a size larger than I need at XXL. The semi dry I usually use is a snug fit.
The XXL was cooler. A lot cooler. I was thinking about WPB bicycle jacket design with built in air pumps from fabric baffles. WPB is usually to warm for cycling unless the wx is cold.
The extra large size pumped air.