One of the more famous Fred Bear tests was when he built a frame packed with calf's liver and used a shooting machine to test various draw and arrow weights. Based on his results, he came up with the "Cipher Rule". He determined that a 60 pound bow shooting an arrow not heavier in grain than the bow weight with a cipher added and not lighter than 10% less (540-600grains). -Fred Bear "YE SYLVAN ARCHER-1943"
Later in life Fred said, "I think the archer should shoot whatever weight bow he might want to shoot, or might feel capable of shooting.....You cash in on the efficiency of the heavy bow only by increasing arrow weights. And in all hunting activities, I like to use a factor “nine;” nine times your bow weight for your arrow weight in grains. For instance, my arrows, 28 inches in length for my 65-pound bow, will run between 575 and 600 grains." -Fred Bear
So it appears to me, that ever since he conducted the shooting machine tests, his goal was 9gpp with a +/- margin, with 10gpp being a maximum ceilling. I think this works well with his recurve bow design.
Absent shooting the largest of game, where published testing talks about a weight threshold to maximize penetration, I think anyone following Bear's guidelines should have an ample balance between trajectory and penetration.
Best