Hi GSIFLIGHT, congrats about your L-39. This jet fly's really well I am sure you will enjoy it very much.
I do not use Futaba Servos only Futaba Radios, I also have the 14mz and I love it, you can do anything you want with this radio. There is a list of recommended servos on the instructions manual of the L-39 you would have to find de equivalent to Futaba, or you could use JR servos, they are great...
For mounting the servos use the recomended way on the manuals, make sure to use hysol or similar to glue the wood parts to the wing.
We used the Falcon (23lbs of thrust) on this jet and it had plenty of power. After a many flights the customer had the chance to upgrade to an Eagle (30lbs) and he did. The L-39 is very overpower with the Eagle and also fly's great. Unlimited verticals with the Eagle.
The jet had a flameout due to an airleak on the UAT and had a rough landing but a new one is on the working bench.

Let me know if you have any other questions. Feel free to contact me at my email directly if you want.

Michel