jf I went out on a limb when I processed my HP5.
I've only used APX100 and Tmax100 & 400 for the last 20+ years, until fairly recently. I couldn't get any 120 Tmax400 when I was in Chile & Peru before Xmas, 120 film was extremely scarce, only 5 rolls of HP5 & 5 rolls of FP4 were available.
I used my dev time for Tmax400/Pyrocat-HD for the HP5 which is 15 mins @ 20°C I was lucky that this was virtually spot on. Agitation is continuous for the first 30 seconds then 2 inversions every 30 seconds.
Hope that helps