I ran my Moki 1.8 w/ 5% nitro Sig fuel (10% castor 10% synthetic), OS #8 plug, and have rpm and thrust reading.

APC 18x6W: 9400, 19.1 lb thrust
Pro Zinger 18x8: 8500, 17 lb thrust

I measured the thrust with a digital force gauge by hooking the hook no the gauge to my tail wheel vertical axle.

My plane is Kange Cap 120, weighing 13.5 lb w/ the Moki. A little heavy I feel. But I have a WM female pilot w/ hair, 3 1/4" wheels, 3/16" axle, wheel pants, large volumn BCM Pitts muffler. Could get down to 13 lb if I go ugly.