I offer free plans for what I call the Pizza Box with Extra Lift (PBXL) or a Pizza Box Foil. You can see some pics of it under "free plans" thread here on RCU. Or you can go to my website and look at the plans there. I have drawings of the landing gear using 1/8" wire. You can omit the 1/2" up turn and slide it into in flute of the 4mm coroplast.
This might help you out with the landing gear issue.
Hope it helps you out.
Kevin