Put a good civilian carb on my drone sportster and flogged it today.

90*F air temp, humidity 60%+, 5% nitro 25% castor, MC59 plug.

Master Airscrew K-series props:
11x6 - 13,320rpm / 2330rpm idle
11x7 - 12,870 / 2370
12x6 - 10,890 / 1890
12x8 - 10,830 / 1700
13x5 - 11,040 / 1590

APC 13x6 - 10,860 / 1850 idle

My numbers are down a little, but I raised the oil content and mother nature raised the air temp and humidity on me. The engine throttled very well and seemed to not like being set 400rpm rich of peak, top end of the midrange would be a little blubbery but recovered 10 fold better than the original drone carb.

Next time I run it I'll try it without muffler pressure and maybe a different muffler.