Congrats on the build Manks and look forward to seeing some pictures posted in this thread .

I agree with Dave and recommend that you do install hatches in the tail section of the fuselage. Though it may be a little harder with the round shape of the fuselage I'd try to find a section and just a hatch out and then glue 1/16" ply on the inside of the fuselage to support the hatch and screws. Then for the hatch itself, laminate some 1/64" ply to the backside of the hatch to give it some strength and soak the corners with CA to firm up the balsa so that the screws will not crush the balsa when the hatch is installed.

I've done this with good success on several of my models.