Plants for my 32g low light tank

Hi,
Here is what I've come up with to put in my new tank:
Hygrophila (sunset, regular, and giant)
Some crypts of some kind
Anubias nana
Anubias barteri
Java fern

Does this sound good for a low light tank, non co2? I am going to get Excel too if I can find it. 40watts of light is what I have. Also is gravel ok for a substrate? There's a beach I can get the awesomest looking gravel at (and it's free.) It's a bit coarse but I'm going to dig down and try to get some small stuff. How many inches should I go with?

 

Hi,
If there are any good ideas out there for diy co2 I'm more than willing to try. I attempted it in the past and I would get great results for three days, then nothing. Or sometimes I would get no results. Once it backed up into the tank causing a huge mess. Since the pH was all over the place because I had no consistent results, I gave up. But I'm willing to try again! I can't get Excel around here so it's going to be expensive for me to mail order it in.