RE: WACO YMF
Bob,
I was thinking the same, putting the fill caps in the wing, but have decided not to. Reasons - extra complexity and finding black silicon tubing of proper size (I think it would be too big). I will probably use some # 12 or 14 solid wire to simulate the fuel lines. You can print the whole thread using the button at the top of the page (no pictures though). Fill your printer with paper first :^).
Ken,
A couple of pictures of a simple fuel dot. This one will fit in anything up to 7/16" thick you can drill a 3/8" hole. To use, pick the plug from the mount and pull out the fill line, unplug, fill, re-plug and push back in until it seats (you can feel it). You do need a little extra line on the fill line of the three line system. Can't be much simpler. The Dubro is similar in concept, but not as nice. First picture is closed, 2nd is open, 3rd is installed.