Thank you for that tip tortron ~ seems you & pennyman got this figured out... Am thinking the panel edges need to be almost an exact shape of the hole it gets put into (?) Maybe I should read more of the forum posts BUT it would also be nice to know approximately how much bigger the panel can be than the overhead hole it goes into (and still fit)... Am also assuming no support is needed in the headliner's center to hold it from sagging or moving... So, the finished product rests on the cab sheet metal border & NOT attached to the cab roof..? Do you think the original headliner was attached to the roof; if so, this would allow more headroom... Those Japanese did some puzzles & magic tricks making these little trucks, ya think..?