One has to wonder whether promotions are shared through the lowest or higher common denominator.
In the second case, combining say a ranged unit with Logistics and Range with a fresh unit solely for the 40% CS bonus would be better than keeping them separated; in the first case, only units with the same promotions will benefit from corps.
I assume health will be 50% of each's current HP too, to avoid hiding dying units in healthy ones. (The formula could be different for support/military combos.)
In the second case, combining say a ranged unit with Logistics and Range with a fresh unit solely for the 40% CS bonus would be better than keeping them separated; in the first case, only units with the same promotions will benefit from corps.
I assume health will be 50% of each's current HP too, to avoid hiding dying units in healthy ones. (The formula could be different for support/military combos.)