Attacked E-4 Hard with a mostly bench carrier fleet - 2BB, 3CV, 1CVL with levels in the 40s, combined with my E-2 escort fleet. Each BB and CAV had a Type 3 Shell, and Sendai and Yudachi had WG42s. I got sent home seven times (that's what happens when your ships are underleveled) but I still cleared it in the end.
The suggested fleet for E-5 is 2BB, 1CV, 1 SS, and one of the following pairings: (Mogami + Mikuma), (Suzuya + Kumano), or (Chokai + Ryujo). Using one of those pairings allows you to avoid a dangerous double airstrike node. I don't have Suzuya or Mikuma, so that kind of narrows it down.
Ryujo is my #1 ship girl forever, so she's ready. But my Chokai is a bit underleveled. I'm going to spend a few days training Chokai up to 65, while recovering resources and buckets. I'll also chicken out and dial the difficulty down to Normal for E-5.
It's hard to find a more mismatched pair than Chokai + Ryujo. The number of doujins of this pairing might be zero. Although I must admit, they did serve together historically, and their skills are complementary.