Hi Kevin,
Go for the 52 tooth - it will drop the gearing slightly, but it won't be noticeable. For years I have been running my Dragonfly with a 16 tooth on the gearbox instead of a 17 - that's equivalent to 3 more teeth on the rear wheel - it gives the engine an easier time without any loss of top speed. (Most British bikes were overgeared as supplied by the factories!).
Regards,
Eddie.