Tryign to figure any monetary course here is silly. It just do not work. In terms of sheer setting up, ships lets say:
Bombers cost without armor what, 10-15 millions? Break it down - Falcata package, 6.4 million, add 600k for new shield, 1.2 millions for guns, 7 millions for SNAC. Lets not count armor for now. 15 millions at this set up.
Rheinland battleship costs 770 mil package, with 18 basic guns, 788 millions. Thats 52 times the bomber.
Though, at these set ups, it takes 45m worth of credits to demolish the battleship without chance for it to survive.