For me on my B7610, I find that I more or less listen the the hydro sound and when it sounds like it is straining or not at the right pitch, I up the RPM. For most work or just traveling, maybe around 1500. For bucket work in 4wd maybe 2000, bush hog at 2300, blade or box scraper 2000, and finish mower up around 2300. I NEVER LUG A DIESEL............God bless.......Dennis