I have a 4# bottle of H335 I use for my 5.56.
I also found the same problems in working up loads, I would read five different manuals and one would be pathetically anemic. Just to be sure, I loaded five of the anemic max loads and shot over my Chrony F1.
Well, I don't remember the exact speed, but I do recall it was about 300-500 FPS SLOWER than the manuals stated for a 55g FMJBT with H335.
I tried load after load and when I finally found what I thought was 1" group at 200 yards, I loaded some up, went back and the group was suddenly larger.
Then, I realized that I am not shooting woodchucks with this gun out to 500 yards, this gun will be 200 yards max, if that! I did hunt deer and black bear with it last autumn. I did not take one shot, but that's another story.