What is more important - numbers of MRP or capability ??
Arc - it's always about capability. Once you have defined what you need, the numbers will fall out to achieve it. i.e, if you need 24 hour coverage of something and the options available include an aircraft type that can fly for 24 hours versus one that can only fly for 3 hours, then clearly you would need less of the former.
Once that is established, you can then look at costs.