I've worked queing at a tournament, and the first thing we need to do is keep this simple. No multicolo(u)red tokens - how much you think a green token would go for on the black market? No inconprehensible acronyms.
There are times when only 1 robot shows up for a practice match. (Including one memorable time when a human player on the no-robot alliance scored the only points in the match.) It's a shame wasting that field space. Other times we were able to combine two matches into one, and get back on schedule - a definite plus.
Recognizing that one team's biggest need is time in the pits, while another team's need is driver practice, why not let the open spots in a match be filled with those who want extra practice sessions?
If there has to be a limit on it, have the lead que keep track of fill-in teams. No team may have more than 3 extra sessions.
If there is a desire to have a link between inspection and practice, make it so that a team must begin inspection before they can use their second extra practice, and must finish it before their 3rd. That would be easy enough for the queing crew to track.