I believe I have sufficient light for the Hygros. They are growing much too
fast. I have to trim them every couple days. The problem is that I don't
want to be constantly uprooting them and planting the cuttings...

You don't have to do that with Hygro. You do have to do it with babytears.

Hygro is one of those plants that can be successfully "topped." If you cut it
back hard, it will grow back even bushier. You don't have to uproot it, like
you do with most stem plants.

I currently have from 25-35ppm of C02 and 2wpg in a tank that's only 12
inches high.

2 wpg might not be enough for babytears. It will grow, but it won't root.
Instead, the stems will rot and it will float up, closer to the light.

If you're looking for a low-maintenance plant, babytears isn't it.

Leigh

http://www.fortunecity.com/lavender/halloween/881/