Ideas Wanted

Our NE TX, NW LA Tractor Pulling Club has asked me to design a pair of universal, Fit any tractor, devices that would indicate when a pulling tractor does a wheelie where the front tire or tires exceeds 16" of daylight between the bottom of the tire and the track. Exceeding 16" would result in a automatic trip to the Dairy Queen.
Having never seen such a safety device on any tractor I have no clue where to begin such a device.
This is another EDGETA insurance tractor pulling safety rule where the person making the rule probably never saw the device the rule requires. I will look up the wording of the rule and post here.
In the mean time I need a few ingenious ideas on designing such a device that would indicate, obviously to the flagman, when a front tire in a wheelie situation exceeds 16" of daylight above the track.
I see the biggest problem is attaching the device equally to any make or style or weight class tractor hooked to the sled.
Your thoughts would be appreciated. The next EDGETA pull is this week Friday.

EDGETA Tractor Pulling mandatory safety rule #23.Front of tractor not to exceed 16" off the ground. A chain device must be used to determine height, DEVICE TO BE FURNISHED BY SLED OPORATOR.
Rule 24 If wheelie bars are used ,chain device not needed.
Rule 25   Wheelie bars are not Mandatory.
I made a chain device for my SFW CA using a 16" light chain. A 30 inch piece of 1"x 1/8 steel flat bar and a big speaker magnet. Don't know if will fit every tractor. Not sure what the magnet will do to a nice paint job . Keeping from running over the dragging chain with a narrow front or a SFW is another problem.

Made ours up lik this bought a big recovery magnet from tractor supply plastic coted so no scratch then attached 6 feet of tlght chain to it on the bottom of the magnet there is a carabiner the end 16 inches or the chain is painted foresent orange leave all 16 inchec on the ground adjusting the chain with the caribiner for hieght as the tractor is moving the chain is draging as the front comes up the flagman watches the chain when the last link breaks ground pulls done       BUT BETTER YET. MANDITORY WHELLIE BARS the guy how refuses to put them on didnt want to pull very bad anyway

I have seen and used what amounts to a jack stand with a pad on the bottom that Slides into the drawbar and then uses a hitch pin. Hook goes into the Clevis on the stand. They had 3 different heights of stands. Seemed to work pretty good. No idea if this would work as tip overs or not for your insurance.