Ken Wallis did some thinking about where to position engines on autogyros especially when considering two small engines rather than one large one. I have a copy of the report he wrote and it shows configurations such as a tractor engine in the nose and one behind the pilot. A tractor and pusher in line astern behind the pilot. Side by side pushers behind the pilot with separate propeller arcs. Side by side pushers behind the pilot with overlapping propeller arcs. Side by side engines driving a common shaft. Side by side engines driving contra rotating props on the same axis.
Of all these concepts he actually built and flew the tractor and pusher in line astern (propeller to propeller) behind the pilot configuration (G-BNDG)