I have just re-examined John Garrett's book "Black and White Photography Masterclass" The vast majority of the prints are from HP5+ 135 film negs, many of which were developed in Microphen and rated at 800

I have seen smaller golf balls than the grain he gets Of course I am judging on print reproduction in a book and I am not a fan of grain in the main but if you are then this isn't a bad combo.

My own experience with Rodinal and HP5+ is limited and based on its grain will remain that way but I'd say it would meet most users' definition of "grain"