I would say the ballast issue is really a non-issue.
Various Spitfires carried different amounts of ballast depending on engine and propeller. Later 109s used a piece of armor under the oil cooler to balance the part wooden tails (no tail ballast needed or wanted). I would be willing to bet that quite a few aircraft carried ballast in order to balance modifications. P-39s could not be flown with guns removed or without ammo unless ballast was used. 60lbs of ballast might not be any worse than a more "elegant" solution, like extending the fuselage ( more weight, more surface drag, better finesse ratio, different elevator and rudder response?) or trying to shorten the engine mount.