Change the timer to 1hr, because 12hrs is just an awful idea, and accomplishes nothing save to further increase side-loyalty.
Change the maximum ENY to 40 (IIRC, its 29 right now), adjust scale so that maximum kicks in at the same time as it does now.
Basically this presents 3 options; keep numbers balanced, horde with higher ENY planes, or switch sides to fly your P-51D's and Spixteens.