Looks like they're coming along ok to me. By the time you can tell the sex, they may be hard to separate out because the root systems are going to be tangled a bit I'm sure.

I'd have kept with the MH because it's more blue spectrum light which is what you want for vegetating plants. You may find them stretching under the HPS.

Note: I'm new to hydro, you're a bit farther along than I am, so take with a grain of salt