Well, I think what you have here is a slightly non-representative sample overall, but it still should give you an indication that HP5 and rodinal can be used to achieve a variety of results, and that you have to play around to find what you like. I make a point of defining my end use clearly. If you are going to scan, you will have a different outcome to darkroom printing. My own results (that are of course scanner hardware and software dependent) lean towards very nice darkroom prints, not so nice scans, for HP5+ at EI 400 with Rodinal 1:50 at 11 min, which I think is sort of middle of the road. My results for the other Ilford films follow the same pattern, with FP4 maybe the one I prefer most in Rodinal. I print up to 9,5 x 12 inches from HP5 35mm negatives, and the grain is not bothersome for me. Your preferences may be different, though. I have seldom found a beautiful photograph (by myself or others) taken on fast film, where I wished it had less grain. Somewhere in the equation of evaluating the impact of a great photograph, grain just falls by the wayside. I think our minds cannot process more information than what ISO 400 film can record. Of course you can print large and then put your nose to the print, but when you look at the image as a whole, that's about where it cuts out. It is maybe the equivalent of 6 MP in digital terms. Someone will have the real numbers, so don't hold me to them. This is just my gut impression.