Hi Jeroen,
maybe Norbert can tell you more about his own experience because it's the same situation for him (737 home cockpit).
Personally, I think it's up to you. The flight plan calculations are based on the indicated aircraft, so there will be differences between different types and you should keep that in mind when flying an A320 instead of a 737, for instance. Also, in your reports it will still say Airbus if the scheduled route is for the Airbus. This is because our script doesn't take the actual aircraft type from FS (not all Pirep systems provide the same data; some don't have aircraft data at all) but the data from your booking.
Other than that there shouldn't be major problems. However, if you want to use the 737 for a route scheduled for, let's say the 747, I'd suggest making a charter flight on that same route instead. Later on we'd like to include a business model for the VA, calculating income and expenses. Using "wrong" aircraft types would then lead to miscalculations.
