Ok. Keep in mind that I am relativity new to a planted tank as well. However to try and answer some of your questions.
Flourite on top of your gravel is not going to help. The problem is that the gravel is coarse and does not hold nutrients for the plant roots. You really need to look for something else as a base and then cap with something else.
As a suggestion, look into using some Mirical Grow Organic Potting mix and then cap that with black diamond blasting sand which can be found at tractor supply for $8 for a 50lb bag in my area. Here's a link
to it as well.
Now as far as you light that you were asking about, if you look here
, it says it would provide low light for most tanks.
Hope this helps.