Pete, do you have gear doors? If so, i wouldnt fly with the gear down at all, F-16 doors are like two huge speedbrakes. I have built/flown 4 f-16's and i would advise you to retract the gear, hopefully our gear has no detectable loss for at least 45 minutes, that gives you some fudge-factor (this shouud be done in the gear up position).

You should aim to land way nose-high on these little f-16's (if You got your cg right). This pic was the maiden flight of my TJ F-16 (These lil things could almost land backwards in a wind)! Good luck, and do-fly it yourself, it is rewarding! Nick