cutting a recess for guts.

I need help on cutting a recess in a golf ball for vampire guts or FHZ guts to sit in.
What is the better/easier choice?
I have the golf ball cleanly cut in half, and both sets of guts.
I need to know what I need to use.

I have
-jewlers screwdrivers
-an electric and power drill
-flathead screwdrivers
and much more stuff.

I also have a pair of calipers to measure the recess and such. I will mostly be doing this by eye though.

Please help me!

Updated. Please help :)!