My first experiments got down to 7 and then 6 pretty quickly, my best 6 being both fast (just over 900 cycles) and cheap (160G)--I have submitted it as a showcase in case it is of interest. After a few days of working on Area I revisited the problem and almost immediately found the layout that makes 5 possible. I had already discovered the incredible usefulness of pistons for this metric when building the 6, and they are required for this no-access debonder setup as far as I can tell. In fact, after a little research I realised that Shadowcluster had already demoed this layout in an ArmA solve for Explosive Phial to great effect. I felt very proud to have figured it out myself, as well as the final bonding sequence which is not immediately obvious.

Out of paranoia caused by this week's Discord discussion I spent Friday and Saturday investigating whether a 4 was possible using waste; I reluctantly concluded that there just weren't enough access points available to make it work. I could be about to take the world's biggie-est L on this, continuing the theme from week 4. But I choose to believe.