As to batteries I run in my 36 inch demon 2 2s 3300 20c rcliops polyrc packs It needed 3oz of lead to balence but that is because im running a light outrunner in it.
The tl50 i have uses 2 2s 3700 20c rclipo polyrc packs with a HET4 motor and a 6x4 prop im pulling about 50amps and have been running like this for over 50 flights now with no problems.
The tl50 required no lead to balence.
My tl40 is running a mega 16/15/4 and 2 4s 2600 10c polyquest packs and required 1.5 oz of lead to balence
Follow the build DVD as to glasing The glassing is what will alow you to go 140mph with out flaping the wing to death it does not add that much weight (My 36 inch demo thread has the bare and glased weights in it).
So build it the rite way and do not worry too much the extra weight will not hurt but actually help the performance on the top end
If you are shooting for a real floaty tl50 then build it lite and use a outrunner like the 450 motor and run it on a 3s pack just move things as far foward as the thicness of the wing will alow for and you may need to cut your motor in a bit farther to get the cg right..
And as to the motor calc stuff it will give you false results (very conservitive) follow the build threads here as the real world numbers are much diffrent that the software will return.
36 inch demon
30 inch unsanctioned
some video of the tl40
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