At one point I actually did attempt to house my snakes together who are similar in size. Despite providing space and multiple hides, the slightly larger one ended up "sitting" on top of the other. I took this as it trying to assert dominance and not wanting to risk their lives, separated them.
Since I was low on space at the time, I still only had one tank. Instead of housing them together I took measurements and bought a plexiglass piece from lowes for less than 5 dollars. I used it as a divider an attached it with velcro so it could be removed for cleaning. It held sturdy and solved the space problem.
Edit: I forgot to mention that these were both female snakes, the "most appropriate" pairing to avoid fighting.