^^did that run a little hot, Steve?^^
At last weekend's TCS in Frederick, which is a good sized asphalt track that had two chicanes and some tight infield bits, I ran a 5.22 FDR. Car was as fast as anything out there (and better than the driver) & the motor came off at under 120F.
For a tight/small/carpet track and a truly competitive TCS legal motor (say 18,300 very warm vs the limit of 18,750 @ 7.2 volts), I'd start at 5.4 FDR and go up or down based on feel (sluggish coming out of the turns? winding out too quickly on the straight?) and motor temp (under 140F?).
With a Red Dot full race (20,000 RPM @ five volts), maybe 6.4 FDR to start. With a Red Dot 15K (15,000 +/- RPM @ five volts), maybe 5.8.