I have driven to events on R888, RA1, V700 and a few others but always concerned with picking up nails, wear the out to fast, etc....I would only drive to events on the Trofeo R's as well for the same reasons.
It looks like they would not be so great in the rain, maybe straight line, not hitting standing water but turning could be "interesting".
I just looked at the R888R, I would not want to be out in much rain on that tire, full tread RA1 would be my choice though I always ran shaved RA1 on track and got great service out of them all the way to the cords, never heat cycled out.
The RA1 has a wider tread than all the above and barely fits my car with the rear camber change and maximum pulled and rolled fenders, sealer stripped off the liner to fender, on 9" wide wheels, the current topic is about 8" wide wheels of course, just mentioning some of this due to the great differences in actual specs versus manf size listings.
Likely mentioned before, the Hoosier R6 I had some old ones for test fitting, would be considered a 240 or wider though labeled 225, simple would not fit but the Tirerack specs which are normally very accurate show the newer R7 to be 8.6 wide in the 45 series and 8.8 in the 50 series where the RA1 shows 8.7 in 45 series and 8.5 in 50 series. I think the new R series is narrower now, likely caused by issues like being outlawed in some classes as overly wide, that has happened before so may of happened again.
It would make matters much easier to figure out if they only published real specs and quite using the current sidewall markings that are significantly misleading on so many tires even within the same model from same manf just different size markings.
I was planning to run the A7 for TT and any autocross events, I could of squeezed on the current 245/45/15, only 18lbs, 9.3 tread so might work well on 9's though optimal would be 10's...they would be FAST but damn expensive at $261 each, ouch!
Luckily I have had great service from JBtires buying fresh barely used take offs from race teams, been doing so for years, even in 285/335/18 for the race Vette the were around $400 shipped, now likely $500 but would cost close to $2k for brand new. Some of the tires were only scuffed, not even raced on, some a few laps, I always picked the best he had because shipping, mounting and balancing always cost the same and I would order enough to be on a pallet when I could to save on shipping per tire.
Savings are not so great on the 15's, my last batch of 8, 225/45/15 shaved, heat cycled, barely used and some not raced on a bit, $800 shipped, $100 each still a damn good deal but not like the big tire size deals. It must be great having a big race budget where you can have fresh tires for every event whether you even ran the tires from the last race or not and have many sets of them!