First question: would you fall into a different class or have a better PAX time if you would use Street tires?
If yes, then use street tires.
Having said that, I would say that R-comp tires are softer, even in colder temperatures. They will most likely not get sticky, but they are still softer then street tires, therfore better adhesion.
So I would think that you will have better grip with the RA-1, but not enough to take full advantage of them if you would get bumped into a different class BECAUSE of them.
If the R-compound tires you are using is getting you into a higher class you cannot change to other tires and be re-classed halfway through the day, same thing the other way around. If you are classed acording to street tires, you cannot change them to R's midway through the day.
If you are comming to the SPDA SOLO II school on sunday this all does not matter, because it is not a competition, and Class and PAX does not mean anything. It would be actually a perfect day to test the differences throughout the day with these tires.
CASC-OR Regional Auto-X Series 2009 and 2010 1st place in D/Mod
Ontario Time Attack Series 2011 1st place in SGT2