If I owned either of those engines I would scratch build a scaled up Screamin' Demon or Diamond dust to 36" span.
Use high power servos, stout linkage and heavy duty hinges on the elevons.
Use hard balsa for the elevons and fiberglass over 1/4" thick balsa fins...[airfoil the fins first].
As far as props go, look at what Steve Wilk at Eliminator props has to offer in carbon fiber.
This should get you going with an easy build and a simple way to see impressive results from your Rossi.