Okay kp,

I'm at work and have to run off from time to time to check on things but I'll try to pass on what I know, which isn't much. I'm a retread, flew CL many years ago and now I'm back. Still fly RC.

As for engine offset, most don't use it, just mount the engine straight to the planks. Maybe put a thin plate under it first to keep the flanges fron sinking into the wood.

I have just finished my first CL in a long time and am waiting for the weather to get good enough to fly, maybe this weekend.

I'm not exactly sure about how much tip weight, I built a weight box in my outer wing tip and right now the plane will laterally balance slightly heavy on the outer wing, and I will probably add from that point about 1 ounce. Maybe somebody else will jump in here and give some more suggestions.