A few of the lever control linkage pins under the control lever cover on my BH77 became loose after not too many hours on it from new - less than 24 hors on the hoe I would guess. Finding that and re-tightening and adjusting them made a HUGE difference on how the controls felt and functioned.
It turned out that the control lever was also contacting the metal cover plate that the rubber boots cover, and even taking the boots off, as they 're what the levers were actually jamming up against at the metal cover, didn't stop contact. The cover was limiting lever travel, substantially.
So I removed the cover plate and left the boots sit there as a basic dust/dirt shield for the valves.
And third, inspect for tightness and lube those lever control swivel pins regularly. I've had to tighten them again a couple seasons later.
I run at operating rpm all the time on the backhoe. 2500 rpm on my B2650. With tight, freely playing and well lubed controls, I've been able to feather that boom swing better and better over time, I'm used to it, and it works great! If needing more careful positioning, I put both hands on the lever with one elbow snug to my thigh and it can be operated very slow and smooth that way.
And on a final note, once I'm tearing along digging a hole, trenching, whatever, having with full rpm the fast boom swing available, is a huge time $aver when swinging to the waste pile and returning.