RT615K+ or R888R for my needs?

I drive my car to the track. Already have a set of proper race tires (Hoosiers) for dry weather.

Need a second set of tires that meet the following criteria:

• can be driven to the track
• work well enough in the damp/wet
• hold up in the dry as backups in case something goes wrong with the Hoosiers.

In my tire size, two reasonable options seem to be the Falken RT615K+ and the Tokyo R888R. I’ve tried each of these on different cars, but never compared them back-to-back. My impression is they’re about the same.

What would you choose?

In reply to LanEvo :

How far is it to the track & back? If they’ll see any serious street miles the RT615K+ would be the safer bet. 

What is the weight of the car. I have had good luck on the street with R888's if the car is under say 2100lb's.

I've only driven 888's once in the wet on the street. They were fairly worn. I thought we were going to die. I've had similar experiences with a few other 200tw tires. 

Most of these tires have a limited ability to evacuate water and that ability goes down significantly with tread depth. In my experience this is less of an issue on course where we're all in about the same boat than on the road where I'm surrounded by F250's going 65mph in a downpour while I'm on the edge of hydroplaning at 45. 

Does a Continental Extreme Contact Sport work in your sizes? They're great in the wet and are supposedly pretty similar to older 200tw tires in terms of dry grip (RS3 era).

Can you get Michelin Pilot Sports in your size?  Or the new 4S's?  Those are really the best rain tire I've ever had, I run the older Pilot Sports on my M3 and they're great.  Did a wet track day with them last season and they gripped well and were very predictable.

A lot of the One Lap cars use them, not as fast in the dry as all the 200tw tire choices, but when it gets cold and damp, they kick butt.

I've run R888s on the street in the rain over here and in the UK.

I'd buy something else.

Also, don't forget that R888 have a pretty high wear rate depending on the car. So putting a lot of street miles on them might not be that great.