The final version ships to customers. I try to keep the experiments done here before actually selling the parts. The final version DOES require trimming the tranny case a little, as the description states - this was a decision made for the greater good as it allows the most motor and gearing choices with the least amount of fiddling. The design itself is very limiting, as mentioned above. Welcome to the forums, too. :)

will it fit a 44mm 2250 lehner motor

Yes, though it has the standard 25mm/1 inch bolt pattern so you would need an adapter. It will accept up to around 46mm diamter motors.

Mike, I am loving this mount! Not only can you use different motors, you can adjust the gear mesh a lot easier. Glad you are here to feed the addiction!