You can use a protractor (Warp Drive make a good one) to compare and set all the blades. A digital level (iPhone) works too. There is a trick of using a yard stick on the back of a blade to mark a spot on top of a cardboard box. Then do the same thing with the other two blades. You can absolutely nail the blade pitch matching that way. Also use the box to look at the tracking on each of the blade tips WRT each other.

Please do look at the cylinder walls. At 300 hours Rotax wants you to do another de-carbon (and replace the crank).

It bothers me that the engine RPM sags after 10 seconds.