When planning an indoor “garden”, there’s a lot of differences to consider, but there’s also some similarities as well; namely space. The biggest downside in my mind, to the 4x4, 5x5 type style, is workroom. If you’ll be doing veggies and different crops, you’ll most likely end up moving plants around as they grow, fruit, etc., and will want ample access to the back corners of the tent for pruning, harvesting, watering, etc., which you won’t be able to reach from the front door. That’s why tents in that category have those handy half-doors on the sides near the back. My advice, would be to just have a little mental exercise working in a 4x4 box, and do some garden planning, like you might do in the wintertime while you await spring thaw. I’ve even grown quite a few cucumbers on a trellis up the back wall in my old 5x5.
If you’ve got room to have walkaround space outside the front and both sides of the tent, then it’s more about build quality and other amenities, like openings for ducting and wires, hoses, etc. Planning for multi-crop gardening will be a different approach than running a single cannabis crop, or even multiple stages of the same crop.
The light is pretty much considered the focal point that the whole garden system is built on, but the environment a tent provides is right up there as well. Best to match them up together in the beginning, then add in all the environmental controls to fit with it.
Not much of an answer, I know, but it’s a tricky question when planning a hobby like this. It’s awesome fun, but can be a bit frustrating if it becomes awkward and clumsy to work in.
A big light, that’s fully capable of flowering the entire tent footprint you decide on with numbers @MidwestGuy was using, that also has a dimming feature is where I’d be shopping. Veggies don’t take near the light, so you might find you only need the full blast of lighting in some circumstances, while finding it harmful in others.