Yep the 26.5 cf5 has a pretty serious end load, but the 26 is more mild. It would probably be closest to the cf3 as far as weighting is concerned. The cf4st I had was crazy hot, but it was very balanced compared to the cf3.
From my experience my cf4/5s were all pretty durable. My cf4st had about 500 on it before I traded it to a team mate and he has put a ton of swings on it since
Cf4 Black is very close to Og J2 with touch of endload. Cf4 ST is like J2U with touch more flex and takes a bit to break in. Very durable and once they start to rattle and get verticals. Look out. Balanced but swings really nice like it has a little endload. Feel is much crisper on barrel than CF3 which I hate my CF3. Barrel feels like mush unless I am hitting a stadium ball and distance isnt even close to CF4 ST. Cf5 is like a .12 with an endload. Very stiff handle and barrel. Feels just like a Sunday Swagger. Really mettalic sounding and a turd until broken in. Than the bat really comes alive and starts to crack. Cf4 insane has no endload and feels like a 24oz. Just like a Mercy in my opinion. Mine killed ball but broke quick. Havent tried Cf5 insane but cant imagine it having more endload than regular Cf5 which is same as OG Stadium.
The CF4 insane definitely has an end load. I swung a 34/24 ST insane and black this year. The black is very balanced compared to the insane. It feels like there is no weight in the handle at all.