Yes, I thought the holes were not drilled in the Horizontal stabs also. Like you I sanded the root down and sure enough there they were and I did use them. Yes, I put epoxy down the tubes to grip the steel pins. I did not note any epoxy flowing into the fuselage but I did not use all that much expoxy in them. I sanded the pins a bit to make them rough so the epoxy would hold a little better. I would say the pins are for location AND strength. I also exposed the balsa between the holes on the fuselage so that it would get a little better bond to the sanded root of the stabs.

The steering turned out to be a non-issue in that the plane tracked straight down the runway on takeoff and landing. Apparently some have added nose steering to the plane. I use a DX7/AR6100 on mine and just used the V-Tail function which required the use of the rudder channel so I just went with the fixed nosewheel.

I was uncomfortable in gluing the wings to the fuselage in the event I ever had to change a aileron servo so I cut small rectangles in the fuselage, reinforced it behind the cutouts then covered it and used tiny aluminum brackets to attach the wings to the fuselage. The wings do not fit the fuselage all that well at the root so I made very thin plywood shims to fill the gap between the wing root and the fuselage being very careful to maintain the dihedral.

I don't think the plane flies all THAT good. I expected it to glide well with the power cut, not the case. You gotta keep speed on it all the time. It does take off and land well. I noted that you really have to keep the speed up in turns.