I think looking at Jetblue, and their mixed fleet of A320s, E190s, and now A220s, is a useful comparison. None of these aircraft are flown by contractors. First year pay is all the same, and then it varies by aircraft size. I won't regurgitate the chart, but if APC's page on Jetblue is correct, a topped-out A320 captain makes $359.40 an hour; topped-out E190 captain makes $287.51. That's 80% of the pay for a plane that carries 66% of the passengers (100 vs. 150).
If we were to add a E195-E2 set up the way Porter does (to pick an example),
with 132 seats, that's 92% of the capacity of our 700, which is what our pay is based on. So I'd expect the pay for that size aircraft to be
very close to, or the same, as our 737. After all, we're flying a plane with 27%
more seating for the same rate! If they want to pay less for the E195, they'll need to pay more for the 800/Max8. Or they could stick with a blended rate and save a whole bunch of money on training costs.
If they expand that to the 175E2, that is appreciably smaller, and probably would pay less. But it still should be flown by our pilots if we ever went that route.