The first obvious options.
Cian 100% and Magenta 100%
From there you have different values that can potentially look your text screened and out of register.
First the screening. I would use either cyan or magenta at 100% and some other color with a smaller percentage. Oranges, greens, turquoise.
A 50% color is a checkerboard pattern, lower values dominate the white or the no-color, so probably try to stay above, let's say 60% so it is more color with white dots inside.
If it is yellow it does not really matter.
Here is an image which is not the exact same case as using a smaller than 100% ink. The problem here is a text converted to bitmap. but it is a similar issue.
You can see the proportion between the screening and the font size.
Try to use bold fonts, not light versions.
You can still registry issues.
In this case try to use just one ink, like cyan at 60%.
Avoid printing on large machines or large paper, where there can potentially be more deformation on the rubber (For example A0 or A1). Try to print on a smaller one like A2.
But this totally depends on the quality of the press, costs, number of copies, type of paper, etc.
Talk to the printer about the specific issue.
