Welcome to the Forum!
I like the 29g, I have 2 of them myself. Not sure about the 30g, I've never had one. There are advantages to both, just depends on the flora/fauna stocking plan you have in mind. I keep Angels and Swords, so I like the height. If I kept Tetras and Crypts, I'd prefer the shallower tank.
I use T5 lighting on both of my set ups. I haven't used the LED's, so not much I can say about your fixture.
I like the Eco complete choice. I use the CaribSea Flora Max, which works well for me. Same brand, different product, but very similar substrate.
As for a source for plants, the For Sale/Trade and ROAK sections of this forum would be a great place to start. I haven't taken advantage of them yet, but I am putting together 2 more tanks and I will get as many plants as I can from sellers on the forum going forward. You know that your plants are coming from people who care about the hobby and their plants. The LFS is also a good place to go as long as you can trust the staff and their stock.
I source my driftwood and rock from my LFS to save on the shipping charges. You can also source it from nature as long as you are doing it responsibly.
Rams are a good choice for the 29g since they can live their entire lives in that size tank. I have angels and I know they're going to have to go into a larger tank at some point in the future. Clown Loaches are not suitable for the 29g. They really need to be kept in a group of at least 4 and they'll get to be huge (12 inches at full maturity). Coryadoras and Tetras would be good dither fish for the Rams.