I had an RV-4 and flew it for 7 years before I sold her

. I even flew IFR IMC... The canopy never fogged. If you are worried get some kind of electric heater you can plug into a Cig lighter jack and direct at canopy.... If you do fog it up, you can clear it.
(Note: You think that idea is weird? An old airline pilot who started on DC-3's told me they used a hose in the cockpit, connected to gas fired heater, to defrost/deice the windshield. The first officer held it up to windscreen as/when needed... I don't know if this is true or was a standard DC-3 system or something his airline added. The idea is the same, get heat onto the windscreen.)