Another interesting point when it comes to D/F brand's and combo's and performance output of any said particular fan/engine combo, is the often overlooked tuned pipe.
I use to race hi-performance 250cc 2-stroke supercarts for a few seasons many years ago and learnt very quickly that 2-stroke pipe design is where the real power is created and fine tuned, as pipe design is very critical.
The same principals of course apply to all 2-stoke engines and pipes regardless of size, So do not over look correctly selecting a tuned pipe design to suit your application. Tuned pipe design along with fuel mix/plug chosen is where performance can be gained or lost.... It certainly can pay off to do some pipe research as well

Cheers-