The algorithm is very simple - it finds the prefix that all the macros share, ignores that and uses the next letter.
If the letter you press has more than one macro, then the palette is filtered to those matching the prefix and that letter, and then the process is repeated.
So if “and” is part of your letters, then you would have to have macros that look like:
X and Y
X Z
Hopefully with the process in mind, you can choose your macro names appropriately to get a good result.
Currently there is no way to tell Keyboard Maestro which characters to use, and it is hard to imagine a scenario where you could specify them.
And number keys do work if they are not being used as part of the macro name. They are not shown in the palette though.
There is a private preference that will have it use each letter in turn rather than ignoring a preference, so if your macros were:
- Purple
- Puce
- Pink
You would trigger them by typing:
- pur
- puc
- pi
respectively.
I don’t really recommend it, but it is an option currently.