Welcome, Dave.
I'm no expert on half VWs, but a 69 stroke x 82 piston dia would be real small, and probably low HP. We had a 69 x 90.5 and it produced about 29 HP, barely enough to fly our LEU. Hopefully, you meant 69x92?
We did not oil the inside of the fuselage tubing. As I understand the practice, this to consume the remaining oxygen in the tubing and then prevent rust, for long term protection. We did not oil the tubing - it adds weight, and there is no expectation that our LEU will operate for many, many years. That's our thinking.
I have seen the flapping wires, brace tubing, etc., in the videos, including one showing the main structure connecting the fuselage to the front inboard wing mounts vibrating violently, which I know they do not do. I think much of this is part of the camera shutter, electronics, etc. causing distortion. There have been builders who have replaced wires with tubing, and other remedies, though. Just keep in mind that you need to build these things on the light side.
I don't know for sure what effect a 4130 empennage would have due to the extra weight. Structurally, it would be OK. The DE's empennage is all 4130. Keep in mind that the flying CG is important, and should be around 28-30% back of wing LE.