I think, with your situation, you should not put up a G5RV. Because
it needs a vertical portion of about 32 ft straight up for the flat
line. Unless you planned to let the flat line go straight down on the
side of the building, a bit away from the walls (18 inches ?) .

You should try to put up a 130 ft wire dipole instead, with a balun,
good coax and a tuner. Then you can do whatever you please with the
ends of the wire.

Can you put your 10 ft support on one side of the building and attach
one end of the dipole to the other side of the building and the other
end in the tree ?