You obviously couldn't be more wrong. Katsuyu is not withstanding the Hirudora by feats, and you haven't disproved it. Chou Shinra Tensei is a very strong attack, but the fact is, that the damage it does is so spread out that the power it outputs per unit area is far negligible, which is what makes it different to say, a bijuudama which vaporises entire mountains, hence why fodders were able to survive it without Katsuyu's aid(can you imagine them surviving a bijuu bomb if they were caught in the blast radius?). It's the same thing with the Juubi's Tenpenchii-it's a strong attack, but it's damage per unit area is low. This is why Madara's v3 Susanoo tanked the Tenpechii without a scratch, as did fodders with a cloak. Yet, a Hirudora from an exhausted 7th gate Gai who could barely move absolutely destroyed Madara's v3 Susanoo. Does this mean that the Hirudora is more powerful than the Tenpenchii? No, it doesn't, but it does more damage per unit area. Same principle with CST and Hirudora. Think of that bed of nails experiment-more nails are more deadly than a single nail, yet a single nail pierces, but a bed does not. Same principle here You have presented zero evidence that Katsuyu is more durable than a v3 Susanoo, and no, "they are different types of structures" is not an argument-durability is durability at the end fo the day. The fact that v3 was destroyed completely, means that to survive it, Katsuyu would have to be as durable as a v4 Susanoo, which withstood the impact of Mokujin slamming a TBB into it, and there's no evidence that Katsuyu has that level of durability.....
The Kisame example does not hold much water either-no pun intended. Hirudora works on the principle of gathering air pressure and is essentially an air cannon. It's much harder to gather air pressure under water. Furthermore, it had to get through Kisame's gigantic GSB first before getting to Kisame-he did not even come close to taking the brunt of the explosion, yet was still paralysed and couldn't fight properly. That, and the fact that he wasn't trying to kill him, explains that incident. Either way, there's no evidence that Katsuyu will protect Tsunade from it, and even if she could be a "meat shield", the first Hirudora destroys Katsuyu, and the second destroys Tsunade.
Edit: I've read some of your other points. The hit lines are obvious in the Madara/Gai exchange. Madara did NOT deal with Gai as easily as you claimed. How do you explain Madara one-shotting Minato with ease? Gai definitely pushed Madara in the 7th gate speed wise a little more than most could, including Tsunade. Gai blitzes and beats down Tsunade with the 7th gate, regardless of whether Katsuyu is summoned or not. Also, using the databook to prove your case is also stupid. It's littered with NLF and exaggerations. What we can conclude is that Katsuyu has a strong resistance to physical attacks, but there's zero evidence that she can tank something like Hirudora, which is like an air cannon and one of the strongest taijutsu-based attacks in the manga.
