I have the .90sp which I am installing in a GP Stuka....broken in but no flown yet......they do recommend installation of baffles to direct the air especally over the front bearing area.
I am installing a balsa baffle covered with epoxy in the cowl to help direct the air. Also opening the rear to allow a bigger space to allow the air to escape.
With the cylinder laying down rather than in the airstream some means of redirecting the cooling air must be provided.