The low rate on the DX5e will help a lot, it sets all of the control throws to 70%, if it were a programable radio I would go for 60, but 70 will help a lot also. The 5e does not offer expo, but there are a lot of people who fly without that so should be OK
The rudder and elevator control arms have multiple holes so you can adjust the physical control throw, moving the arm in closer to the control surface will reduce the amount of surface travel, but the aileron does not have that. I have my rudder and elevator control points set at the second in from the outside, which I think is the stock position. I would try the low rate in the stock positions and see how it works for you, adjust them in as you need to if it is too twitchy.
I do not know of anything I would do to try to limit the physical travel of the ailerons independent of the servos.
I attached a picture of mine showing the battery position and the CF on the tail.