Results of my test of 10 year old HP5+ (storage unknown) in film developer Rodinal 1:50 16m 20C and print developer Ilford ID-62 1+7 8m 20C.
The first attachment shows the fog levels by photographing the developed films on a light box.There is little difference, 10 years old film did not give a significant problem.
From prints, there is little difference in grain either.
I like the more contrasty print developer as giving a more "fine art" look, second attachment,it may be coincidence.
So IMO HC110 probably is the best for low fog combined with finer grain,better than these two developers.