-That defeats the whole purpose of having a res imo. If youre that worried about getting all the plants you can in add more sites.
-This will become more obvious once you get to that stage yourself. Its not bad when theyre little, but unless you plan to grow some half assed tiny plants it does get difficult and annoying to get into the site when they grow up especially as the start putting on bulk on the top. Do you want to be banging around the tops of your plants and damaging your nice top buds or branches bending over in half maybe even snapping off? Opening sites and exposing roots to light daily or more often for ppm/ph checks also makes you much more likely to get algae growth you dont want.
-You dont want your control res under your lights and in the warmer temps if you have room. Usually the space outside is a few degrees cooler than inside the tent (nearly 10F in my space), keeping the res out there make it act as bit of a radiator and is just another step in helping with temp control. Space vs water volume gained on the size of the tote. The outside res stays the same water level as the rest of it unless you do a very specific build. Adding a bigger outside res will only add a few more gallons.
A lot of us use these Home Depot totes as theyre easy to get for most ppl in NA. The one you mentioned has a 15x20x11 ¾ option. Thats the only size I see that id use. Its pretty close to the 17 gal totes I use.
This heavy-duty HDX 17-Gallon Tough Tote is designed to handle all your storage needs. The recessed lid enables you to stack multiple units effortlessly, while the tapered design facilitates easy nesting
www.homedepot.com
I use a big 55 gallon tote because it fit well in my space and I use half of it to chill my veg system if I run both at the same time. Its completely unnecessary and ive thought about changing it for a smaller one many times. As it stands it works and I dont have a reason to spend money on it so ive left it there.