For a grid at personal range I would say 1 square is 3 meters x 3 meters
Engaged - adjacent squares (i.e. CC)
Short Range is up to 2 squares (6m) between characters (i.e. CXXC)
Medium Range is up to 12 squares (36m) between characters (i.e. CXXXXXXXXXXXXC)
Long Range is up to 22 squares (66m) between characters (i.e. CXXXXXXXXXXXXXXXXXXXXXXC)
Extreme Range is 23 or more square between characters is extreme range.
To help movement work with using a grid, I'd say that characters can move up to 10 squares as a maneuver (base movement of 30 meters), though moving from Engaged to Short would still be a maneuver as per the core rules.
The problem with that break down is that moving from extreme to long range is 2 maneuvers, Moving from long to medium is 2 maneuvers, then from medium to short is 1 and short to engaged is one.
Some change has to happen as the way the abstract range bands work by raw, there are points on a map where one step would technically be 2 maneuvers. Plus the maneuvers required don't always jive with the distance covered. This is fine for abstract, but does need some tweaking when going to a grid. You could add more spaces between ranges, but that doesn't fi well on a battle mat. Or you could lower the number of spaces a person can move to 5 (15m). Probably lowering the amount a character cna move would be the better fix to make it fit on a map.
Nextime also please to offer up some constructive feedback. If the breakdown is a problem, then be useful and try to offer up a solution.
You stated that :
I'd say that characters can move up to 10 squares as a maneuver
But by your own CXXXXXXC Examples, a Character would be able to go from Long to medium range in 1 maneuver. Instead of the required 2.
Assuming one was at 22 sqaures away, and they used a Maneuver to for 10 squares... that would put them at 12 squares which you have as 12 Meters. When it should take 2 maneuvers to reach that from long.
You need to be adding each category to the next... it works for medium to short.. but not long to medium..
Medium is at 12, then Long needs to be at 32 and Extreme starts at least at 52 to Account for said 2 maneuvers at 10 squares.