Pyro:
Hmm. In the interests of making it simpler yet somewhat realistic, how about this:
A recon loadout would strip your guns, giving one a bit more performance, but it would also give one a 'bombsight-like' ability. Depending on how various aircraft were actually fitted with cameras, a pilot would have specific 'views' from which to see through a zoom-lens, much like a bombsight with various magnifications. For example, a Spitfire might have down-view and port-view alignments when looking through the camera along with the ability to zoom in for a better view. Any information could then be radioed to whomever needed it.