Well, I took two new engines, a TT 39 and OS 32 to the field and mounted them to the test stand for break-in. After 48 oz of 15/18 Powermaster in each engine I started some testing. The OS broke-in nicely with great idle, transition and power. The TT will take a lot longer due to the ring and has not reached its peak yet; the engine gets noticeably better every run in all factors.
Both engines will reliably idle at 3,000 RPM. Both with an OS #8 plug, using the same Mac's pre-tuned header (cut 1/4" shorter than supplied) and Quiet pipe kit. RPM backed off 200 from peak. Here are some results.
OS 32 SX 15% nitro
16,500 with 9X6 APC
17,700 with 8X8 APC
TT 39 Pro heli 15% nitro
17,100 with 9X6 APC
18,200 with 8X8 APC
TT 39 on 30/20 Powermaster heli fuel
16,700 with 9X7 APC
17,500 with 9X6 APC
18,700 with 8X8 APC