FMS FJ40 - Stock Servo Arm Sheared - what is a suitable replacement?

As the title states, the stock service arm broke during an impact while driving like a crazy person through snow and ice filled back yard. The fun came to a stop when I impacted a large brick. lol

I know the general specifications for the arm. The stock one had a 20mm hole spacing with M3 threads. , It is 6mm tall at the servo end that tapered down to 3mm at the linkage end. The service arm also has to be below 30mm long due to clearance issues.

So I bought a few aluminum arms, only to find that they do not fit over the servo drive gear. What size/ teeth count does this have? I purchased a 25T servo arm, but it would not even start to go down on the servo.

I plan on replacing the servo eventually, but I want to get my FJ up and running soon. Any help would be appreciated.

Cheers...