SteveFass:I'm following this thread too as also interested in the Slipstreams.
The OMS website says it comes in 4 sizes, but after a search around the internet, only two sizes are sold, XXL and XL. Further, the description at Leisure Pro calls it L/XL. I wonder if OMS decided to only offer two sizes and make the XL a tad smaller.
You are right...OMS currently has 2 sizes available and is waiting for enough sales to justify the $30k in tooling to do the next size which will be med/lg.
If you want med/large then send OMS an email asking for them. Customer input is always important.
The XL is a standard XL if not slightly bigger. My XL SP fins were always snug when I went to pull it off but I have no trouble pulling the OMS slipsreams off. Others have told me that the fin pocket is a bit bigger than the SP fins.