I've run a Mars II 1600W 5W unit for over a year and half plus in a Mars 5 x 5 x 7 tent. It's honesty perfect for that tent size. Personally, I would suggest multiple smaller panels versus the one large one, not only does that safe guard you a bit in case you have panel troubles, you'll have better light spread. I've honestly run into a few heat issues with my unit (another reason I'd suggest smaller ones, this unit is large, heavy, and puts out some heat!) but
@MarshydroTina has been more than fair with giving me options to get it fixed even if you do decide to go with one big unit instead.
I recently received a 5 x 10 x 7 Mars Hydro tent, it was very discrete. Only had Mars Hydro on the label. The shipping company (I'll have to check, want to say this was UPS) however sloppily drug it across yard, letting the box RIP OPEN, pretty much showing what was inside. So I guess, maybe keep your local delivery drivers upper arm strength in mind too lol!