Well, I've had a chance now to drive a few full 28-lap sessions in Free Practice. The weather is definitely scripted. It was identical in every session I did.
The rain is heavy for the first 17 laps of the race, keeping the moisture gauge pretty much pinned at or above the second tick. From there, the rain lightens up and the gauge slowly drops slightly below the second tick. On the radar, the rain moves completely clear of the track on lap 20. The moisture gauge steadily falls from there, but at the end of lap 28 it remains above the first tick. It isn't until lap 30, or so, that a dry line becomes visible on the track.
I feel like this is different from the race we had in January. I thought for that race even in Free Practice the dry line started to appear before lap 20. I'll have to go back to the forum chats to check, though. I could very well be misremembering that.
Anyways, if Saturday's race follows what is in Free Practice, it's feeling like 17W-11IM would be the way to go. Of course, I have no idea how well the IMs will last, or if having all those other cars on track will cause it to dry faster.
Luckily, I'm in the last region to race, so I'll have the benefit of learning from streamers that run earlier, and adjust accordingly. Good times.
