Well I am no expert but all I can tell you is when we have heavy rain at Cadwell i have a much better setup than the small single seaters and little motors based on the number of cars I was able to overtake.
Partly because I am running PS4S or Conti7 and my car is heavier than these other motors.
Also a lot of people came with Semi Slicks vs my normal road tyres which defo give me a better grip in the wet, downside is when it dry's out then the tables can change..
Finally I do try and use the wet line vs the Dry line on the track which does seem to offer a little
help.
Or maybe its because I know the track very well and others are being cautious because they don't