Lovely contrast.
I think MaiTai, being a softer insert (at least when compared to 7RP) is more suitable in a smaller bag. In a B35 (which I have), the insert doesn't have sufficient firmness to support things inside the pockets. What I do with mine is to leave the pockets empty, all my items lay flat in the main section. At least it prevents the "walls" of the insert from flopping inwards.
Hope that helps!
I like larger bags. I have mostly k35 and b35. I use Mai tai inserts in all of them and I keep the pockets filled with my essentials. I don't have any problems with them flopping in. I keep my wallet keys and phone in the center portion. I don't use small leather goods because the pockets hold things securely for me. If you are putting things into SLGs first then into the pockets perhaps it's too heavy for the side pockets?