> Could constant agitation possibly be the cause of the increased grain I'm seeing with HP5+ in D76?(posted 8478 days ago)Nope.
> I'm processing the stuff at the recommended 20 degrees in a Jobo processor. I've finally controlled the contrast to an acceptable level by reducing development time
I found that HP5+ requires a 25% reduction in development time (from intermittent agitation to rotary agitation) to match CI and curve shape. Could be you're overdeveloping but since you didn't have an intermittent-agitation starting point with the film that you know works the problem is that you don't have anything to compare it to. You might try reducing the development time by a further 10% or more.
> Incidentally, I'm over-exposing the stuff 2/3 stops more than the recommended 400.
Stop doing that unless you have a good reason to do so, such as insufficient shadow detail when the film's exposed at its rated speed.