For HP5+ try 7'15"/75F Rodinal 1:50. I don't recall the EI for that but I think it was about 200; I ordinarily add 20g/L sodium sulfite to the working solution for this combo to get EI 320. It isn't enough sodium sulfite to make mush grain.(posted 8729 days ago)My only experience with Delta 400 in Rodinal 1:50 gave grain that looked sorta like oatmeal.