I am currently flying the Nelson Head/Brodak 049 Mk 1 on my Sky Sport.  The prop is a C*x 5x3.  Performance was so hot on 45 ft lines, I have gone to 48 and will probably run out to 50 ft!  This is on 15% nitro 20% oil fuel.   Lap times are about 4.6 seconds.

On these long lines, I will have to de-tune the controls still further.  The wiggles show too much as the model has so much more room to fly than it actually needs to make the maneuvers.

It is only the .049 while the Wasp is .061.  I am very pleased with the power and the Brodak and Wasp will probably become my standard engines in those two sizes.  I have 2 of each, and, barring crash damage, expect them to last a long time.  Certainly the performance of the modified Brodak is excellent.

It is hard to judge the Mk II because you are stuck with the stock plug.  I suppose it is fine for casual sport flying, but lacks the performance of competitive engines such as the Big Mig or Nelson Modified Mk I.