I don't doubt that you did alot of research: I have too over the years, and continue to read about these wonderful creature. Probably in part because I get my information from different sources than you, we are of different opinions on the subject of glass tanks.
If a glass tank is what you have, then by all means use it. What will you be using once they outgrow the tank in a few months?
I used to use a 45 gallon 'breeder' tank for the first hatchlings I had here. I only used it for one season because I found it to be too problematic in such a variety of different ways.
I now keep my hatchlings in Rubbermaid totes (opaque sides, wide opening at top for good air circulation, very portable and easy to clean, reusable, non-breakable, inexpensive, more 'floor space' than glass tanks of comparable volume, etc., etc.). Glass tanks just fall short in many ways.
When warm weather arrives, I put the youngsters outside for several hours per day.
My adult turtles stay outside year round in a 1000sq. ft. habitat.
No photos at this time, but you probably know what a Rubbermaid tote looks like.
A note on the websites that you referenced, though:
One of them states that a small (20g) tank is adequate for a box turtle, and does not specifically state for a hatchling or young turtle only. That size container is woefully inadequate for an adult turtle, but they don't differentiate.
Another website that you shared with us states that hatchling box turtles should be kept in a tank with 1" of water in it. Box turtles terrestrial (albeit semi-aquatic) and should NOT be kept in water. That is a recipe for disaster, in my opinion.
Yet another site recommends feeding canned dogfood, corn and other food items as a regular part of the diet, that should be fed only sparingly, or avoided except in a pinch.
With the exception of Tess's, these are not websites that I would recommend that a turtle keeper turn to for accurate information on turtle care.
Sorry.