Hello Justin,
I am no expert, having returned to the hobby after a 40 years gap. However, in my 125L I have crypts, vallis (straight and twisted), bacopa, and various amazon swords. All are planted in 2-3mm dia. gravel, nothing else. I did, like you, add fertilizer to start with, and add it occasionally now if I think there is a need. Initially, all the plants looked fine, but after a short while both the crypts and the vallis "melted", as they lost their initial leaves, although I think the vallis melt was caused by some bad advice from elsewhere to use "liquid CO2". Now, 7 months on, all the plants look great, and I am having to prune regularly. When you have added all of your plants, you will eventually discover which ones suit your set up, and which don't.
One more point, a lot of ferts contain nitrate, so make sure you keep an eye on the levels. Most of the time your fish will create all the fertilizer that the plants need, once everything is established. It can take a while!
Skittler