Personally, I wouldn't put a 600 mAH pack in your TF P-47. Think of it this way: Is your plane worth a couple of extra bucks for a larger pack?
I put 1100 mAH packs in all my .60 size planes. The control surfaces are usually larger and due to increased air pressure when deflected, the servos will draw more current than in your LT-40.

A basic way of determining charge time for a wall wart and a packs is as follows:
Charger output: 50mA
Pack capacity: 1000mAH

1000mAH X 1.5 = 1500mAH
1500mAH / 50mA = 30H

However, since the charger's output is below the C/10 charge rate, 40 hours may be a more adequate charge time.

Check out the Battery Clinic.