The screw with the cone adjusts the throttle arm's idle position, it has no internal function. The other screw adjusts the low rpm mixture, it should be at about 1 and a half turns out as a starting point and then adjust an eighth turn at a time (trial and error, prop on) to get a compromise between smoothish tickover and immediate response when throttle opened. Screwed in will richen, - too far and tickover will be "chuggy", go too far the other way and tickover may be more "purring" but wont respond well to throttle increase. The main mixture is fixed by the size of the jet fitted. A carb kit would be a good idea if it is the original one thats fitted. Max RPM should peak around 9400.
I didnt go to the fly-in, I hold my hand up as one of the undoubted many who was put off by the weather given the distance - I love a party with like minded people but if quality flying looks unlikely then there is only a certain distance I would go.
Nige