Get a Ramoser prop , out performes everything...
5 blade and scale and you can set pitch , engine runs cooler , and more torque.

this thing can really go slow , make sure your CG is correct. on the tube or just in front.
set flaps at maximum , use Crow like i did , raise Ailerons 10mm each side.
even with 25% throttle i can set it down with less then 30kmh ...
you can see in my video thats with 25% throttle..

BTW : Did you open the cowling on the underside? where the wheel retract sits? this makes a HUGE difference.
you need to draw the heat out of somewhere.