Interesting Idea...
We are also hosting our Pinewood on the 26th here in Poplarville, MS. I will check with my ACM ( thank goodness he's an engineer!!)and maybe we can hook up.
Also, never heard of tin can method for bracketing, my engineer has rigged up our track to his computer and his EXCEL spreadsheet cycles the boys through the 3 diff lanes - it even converts it to MPH & displays on tv screen.
I do know we have to use 1-2 dummy cars to load balance the lanes at times ( keep them at 3oz or less to ensure they do not win...)
good Luck