Ok my head hurts now from reading the last 50 pages or so. I believe I read on here(can't remember when) that someone is using fuel tubing as an o ring replacement? I have a stock 7port believe gen 4 or 5. I run on 20% with only 1 copper shim(plus button) i believe .4mm total as i recall. Are the carb settings given in these last few posts ok to start with on 20%? It seems that most of the posts refer to 30% I'm using 20% as I was told that it is easier on the engine. Is this correct, my boys and I don't drive well enough yet to need the extra power of 30%. Just looking for reliability and ease in tuning. We run OD plugs 97T but just ordered 77T's also and engine usually only gets to 190 or so.