When I had both of mine I had LS and LR thats all I had in the tank They move stuff alot because they like to make there own "shelter" So I was sure not to out huge pieces in by they were big. Neither of mine escaped in the 3 years I had them. I didnt even put a tight lid or anything of that sort on the tank I just took really good care of them. They are also very messy eaters so a protein skimmer is no a bad Idea. make sure that all tube for filtration is covered with something with tiny holes like a piece of pantyhose because they will try to go up inside the tubing to hide, and believe me they CAN fit! Just always remember this as well. They have a huge surface area of skin, think of it this way turn your skin inside out and think how sensitive it would be, thats how an octo is. so always make sure your ph and alk and stuff are ALWAYS on!
Good Luck if you need anything else let me know
btw you can train them very well too!