.........if its gonna pi55 down all day then you should fit full wets and get out there.
If it looks showery and may clear up later, then I'll wait and then go out on the SCs.
It would be a shame to waste an entire trackday (and obviously the money associated) by not getting out at all - so I take wets with me.
Also - I'm selling a pair on the Market Place - Jon - you know you want them!!
There is a kind of intermediate position and thats to use 207RRs or similar, plenty of grip in the wet.