I built the ARF and didn't have the problems you have indicated. However, I did dry fit everything before hand. I added a sullivan tailwheel assembly to the plane, but had problems because of a single ply bottom on the fuse. I ended up drilling a hole through to the stab shelf, guling the dowel in place then sawing it off both top and bottom then sanding. On the servo side, I ended up adding a bulkhead just behind the servo tray to hold the nyrod outer casings. They flex way too much when the servos are in operation. In addition, I added standoff brackets to hold the throttle cable casing in place as well. It also flexed way to much for good throttle response. I also replaced the nyrod pushrods with 2-56 rods using the same outer casing. I got tired of re-trimming under different temp conditions. (I don't believe others that say the nyrods don't expand and contract. I have seen it happen.) I also reinforced the gear block with fiberglass cloth and epoxy after the whole thing came out on a rough landing. Lastly, after mounting the motor (I have an OS91 surpass II on my 4*) I ran a wooden dowel across from the left side of the fuse cheeks to the right and used cowl mounting screws to hold the cheeks steady. They kept vibrating when the engine was running and the fuse started to come apart on the bottom front.

You'd think that after all this I would have nothing good to say about the plane, but I love flying it. I know this seems like a lot to do to improve the ARF, but I find I am doing a lot of this with many of them anyway. Good Luck and hope you get it to the point you want.