Quoted from EricR:
Thanks for the tip, hopefully at some point I'll have a chance to use it. I have to admit its a little demoralizing to think about qualifying a 5th CIU when I've yet to start a 4th. Having to go through that extra step seems just mean lol.
I've been thru 4 CIUs a couple times and it is brutal to drain out lighting the 5th/EoL.
The best strategy (imo) for extending a game towards EoL on typical home settings (ie - EB's are on) is explicit focus on coffin MB. Any time you start another MB, bash the coffin as fast and as often as possible to get the locks lit, progress to the first EB (~15 coffin hits), eventually progress to the second EB (100 coffin hits), and progress the coffin CIU requirement. The game I made it to EoL I think I had like 150+ coffin hits by the end of it and had played 4 coffin MB's
Coffin MB also has the advantage of being able to be extended both by the snake add-a-ball, and stacking another MB, so you get tons of ball save time, and a very long opportunity to light CIU without fear of ball loss. With decent play, almost every coffin MB should end with CIU lit, especially if you bring another MB into the stack. Once CIU is lit you must get in and out of it ASAP and get back into the nearest MB you have. Try to use the CIU ball save time to light the 4 'exit' qualifiers and get the hell out of the mode while the safety net is still there. #1 rule is do NOT start another MB if CIU is lit - you want it available immediately after exiting CIU.
The biggest wildcard is Seek and Destroy. If you start Seek and Destroy after the 3rd or 4th CIU and it expires, you have a hell of a climb to get CIU lit again. Its a tough mode to try and control the start of so I usually just let it happen when it wants to and hope for the best.