OK - another temporary possibility if Todd can't get you the replacement wire as quick as you would like... how much clearance is there for the "arms" when the gear is in it's retracted position ? What I'm thinking of, is that if you can't get the wire longer, can you get the arms to be "higher" by e.g. C.A-ing a thin plywood tab on top of the arms ? With the right CA it should hold well enough until you get the replacement wire, and CA solvent can be used to clean the arms up afterwards when you remove the tabs.

Another "imperfect" and inelegant solution to be sure, but it might get you going in the short term. If you do try this though, please test that you have proper adhesion on the tabs, as you wouldn't want to lose ground steering due to an insufficient bond.

Along similar lines - could you "extend" the spring very slightly by crimping / soldering / whatever a thin brass tube over the ends of the wire ?

Gordon