After booking a trip, I spent some time perusing the CO timetables, and I'm a bit curious about how different 737 models are allocated to different routes. I'm not talking about models with different capacity - obviously a 738 will go on a route if a 733/73G consistently goes out oversold. What I am talking about, is the 733 vs. 73G.
For example, all of CO's IAH-DCA frequencies are operated with the 73G. However, all of the IAH-BOS flights are 733. Both models have the same capacity, within 2-3 seats anyway. I have flown both of these routes, and while having the 73G for the 2.5 hr flight to DCA was great, I feel that the added amenities and IFE in the 73G would be more appropriate for the 4 hour haul to Boston.
Are there differences in the premium cabins on these aircraft- for example, does the 73G have more F seats, and does the DCA route have more demand for upgrades and F seats?