IMO 3.5lbs is pretty light for a big double.
Personally I like 4-5 pounds for both front and rear triggers on a 470NE double.

Thesedays a lot of the 'new to doubles' guys want their DR trigger pulls really light, some times 3 pounds or lighter.
At that weight it is no surprise that some are having occasional double discharges as well as accidental discharges.

If the two doubles were mine, I'd prefer them both to have similar pulls of between 4 to 5 pounds.