i didn't add wieght to the tail of the plan when i moved
the CG back.
i relocated my battery pack or RX and kept it as close
to the fly able CG as much as possiable.

this way... there wouldn't be a drastic shift in the CG
as the fuel runs out if i was to simply add lead to the tail.

i'm not sure what the ratio is,,between wieght in front or back.
the cg is not at the haft piont of the fuselage..as we all know.