My experience is with the Hoosier SM7s, which are the same compound as the R7s. 

With the Toyo RRs, the sticker tires are about 1/2 second faster than 20 heat cycle tires.  However, they degrade very slowly over the 20 heat cycles.  Beyond 20 cycles they get very slippery very quickly.  For me this was about the same time as we're getting to the cords.

With the SM7 there is about 1.5 second difference between the sticker tires and 12 heat cycle tires.  The SM7 stickers may be a 1/4 second faster than the RR stickers.  I suspect this is not due to the  compound, but because they are about a 3lbs lighter than the RRs.  After about 12 cycles on the SM7s I was hitting the cords, but they were slow enough after 8 cycles that they are only good for practice tires.  As best as I could tell "breaking in" made no noticeable difference.

I'm a big fan of the RRs over the SM7s.