How to Airlines who operate a mixed fleet of A320 and A330 from the same pilot pool tackle this (Monarch, Iberworld, etc) ?
Not completely familiar with the situation but it seems fair that basic salary should be the same with sector pay higher on the days you operate the '30 because of the greater distance. Overall productivity about the same, say the 10 sectors you operate the '20 in 3 days equals the 2 sectors you operate in the '30 in 3 days.
As mentioned above, it gives the 60+ chaps a change to go back to short haul and sleep in their own bed's every night without taking a pay cut.