I'm using the same boots you are, and I agree the inner lace system is very good and can actually be overtightened.
As far as the outer laces go, the bottom ones should stay decently tight. Once you get to the first set of hooks try to pull them as tight as you can and then lock it into the hooks to retain the tightness. Try not to use the hooks as leverage to much because tightening this way is hard on the laces.
Hope this helps.