Sending 3 bytes worth of data in 6 characters is not more efficient than sending 3 ints worth of data in 6 bytes.
ahh yes, because I was also dealing with text elements I got it stuck in my head that every character was a byte.
Sending 3 bytes is even faster and even simpler to decode, just shift the 3 bytes by 2 to get your 10 bit range. You don't have more granularity anyway.
Do you mean simply like this:
255<<2 = 1020?