Well we could solve both problems by moving to duodecimal mathematics instead of decimal.
You
save one digit on every LED clock that way, which saves space and actual resources. You can use a stylized A for 10, and lower-case b for 11 then on led clocks, which is in line with hexadecimal too, thus making computer science a
little easier to explain to the masses while you're at it.
Then, you make a
new SI based on powers of 12, with the inch/foot as the unit of distance, troy ounce/troy pound as the unit of mass, and then "decimalizing" time under your new system is a little more familiar.
But, you know what I'd do then is actually express all dimensions as powers of 12 of the
planck values, so that things are tied into the universal measurement system. The advantage of this system is that
5 of the basic physical constants are set to
1 under this system of units. If you use these as the basis of an improve SI system then you get the advantage that many physical constants can be expressed as 1.000... to some power, thus making all physics calculations both simpler and reducing computation error.
12^36 planck lengths for example is very close to 12 KM. So I would use that as the basis of mid-distance expression. 12^33 plancks is about 2 inches, which is reasonable for measurement. 1/144 of that is half a millimetre so plenty accurate for day to day engineering with two decimal places. This is just to show that shifting to a system where most of the fundamental constants of space time are nice even numbers with clean powers in SI-type units doesn't have to leave an unworkable system.