As far as pay rates, what Delta has now is way too complicated..... what I'd do....
4 categories, with overrides.
> 50-150 seats (mostly narrowbody north america flying)
> 150-250 seats (large domestic to europe and smaller asia flying)
> 250-350 seats (most large international flying)
> 350-450 seats (large long haul)
10% (or whatever you choose) override for international flying
20% (or whatever you choose) override for intercontinental flying
Of course, all these numbers could be tweaked to your pleasure. Theres no need for dozens of different pay scales, there are only 4 or so real categories of flying a major airline does. Alternatively, if you don't want to base it on seats (seat counts change, similar seating planes do different missions...), you could could make 4 MTOW categories and do the same sort of deal.
0-199k lb
200-349k lb
350-599k lb
600k+ lb