Of positive integer bases binary of course would provide the biggest bump from 10 to 11 a full 50% boost.
However I would consider ternary as well because you still get a substantial 33% boost and 11 is 4 which is death. And what's more black than turning your amps up to death? None more black!
To Kozmos from post #28: Why not go for base 69 or base 420?
Even base 60 is too large, you need 60 unique symbols for that which will cause the additions and subtractions extremely hard.
Any odd base will make the number-rounding really complicated.
To Perfection from post #32: The real benefit of base 12 is that division by 3 or a power of 3 never results in continued fractions.
Division by 2 or a power of 2
Division by 3 or a power of 3
Division by (2 * 3) or a power of (2 * 3)
Thanks a lot, that gives me a new sub-project to work on. Check out the 1st attached image below, that's for you.
To Borachio from post #40:
3 * 5 = [dec] 15 = [duo] 13.
The duodecimal 13 is a composite number instead of a prime. So we have a luckier 13 there.
Isn't [dec] 13 being unlucky just a tradition?
Chinese people believe 4 and 44 being unlucky.