Well ...
I have been using 2100mah LiFe (3.3v/cell) pack.. For my power hungry servos (jr8711) , I used to get 2... May be 3, 7 minute flights out of it. 3rd had to be very calculated.
Now this 3600mah LiPo (3.7v/cell) pack now which I am gonna use with an align 3in1 (basically a ubec with glow igniter) will give me may be 4 flights .. Which also has a battery status indicator light and on off switch and all.
That means for you.. In your electric bird.. You are looking at about 3 minutes a flight so: so close to 7 flights on LiFe packs and about 8-9 flights on a 3.7v system ..
Your heli.. Might consume less power on the receiver packs. I saw you were looking at BL servos and savox servos.they are less power hungry. When you do fly it. I would recommend flying your bird it's first flight and then charging right away and seeing how many mah you put in.. To see how much it uses in a flight. The max you wanna calculate for is 80 percent battery capacity and do one less flight for having wiggle room.
I had a crash on my vibe three weeks ago when I didn't realize how much I had idled the heli as I was setting things up and tuning the engine, and my beast started having a stroke when my power level went below a certain value and didn't have a battery indicator to show how much is left. Man I have been really watchful and paranoid since then.
I was gonna put that 3800mah LiFe pack in (the one on sale) but I ended up getting this offer with my engine so decided to sell it.