I am a modafinil user, I would not suggest using this for bodybuilding or training at all!
First off, the half life is 15 hours, and seriously, I take this (200 mg) at 4 or 5 in the morning when I use it, and I can't even fall asleep at midnight. I only use it when I will have to work or write all day.
Second point, it really surpresses your appetite and you will have to force down all food (even when cutting, I have tried this)
It makes you super dehydrated, and you have to drink so much water, seriously I piss every 15 minutes sometimes when Im on.
You will not get energy from modafinil, it will only enhance your cognition and make you ultra focused, for tasks such as work, writing etc.
The side effects from modafinil, appetite supression, lack of sleep, and dehydration, really does not mix well with lifting if you ask me.
That's just my 2 cents...
I love modafinil, and as a student it really gives me a huge edge, but for lifting? Then it is IMHO a waste. use it for those days you need to work a lot, because it really does you no good for lifting, because of the side effects