Help battery placement on my build

[Firechief51]

https://www.rcgroups.com/forums/showthread.php?3417009-Battey-placement

Look at the photo on the above attachment and let me know what you think I need help. My concern is I got a cut through a lot of structured air it's tripled up. And I can get one battery up in the fuel compartment. The wooden blocks represent the size the batteries I'm interested in 5000 mA 4 cell
Put one big battery in the fuel compartment say a six cell and two small to cells right and left of the motor just saying. I know the placement of batteries is critical for the CG

[larryrose11]

Tough one.
A better picture would help for sure.

[NativePaul]

I don't know that particular boat, but scale hydros typically want the batteries as far up front as you can fit them.