Congratulations on your purchase.
I've got a B7610 with a B4672A backhoe. I've also operated a few small tractor rental units.
There has been a hot debate on and off here a few times about the speed at which to operate your engine at while running the backhoe. It comes down to experience and speed.
For a beginning backhoe operator, the backhoe will be jerky to operate at first. Try the first ten or so hours of use at ~75% of PTO speed, which in my case is around 2,000 rpm. This is just to keep the bucking down as you learn. What happens is at first you tend to operate only one spool/valve/cylinder at a time and all the pump power goes to that one cylinder and it operates real fast--too fast--especially in swing and boom lift. So, running at slower speed, things slow down and you get used to feathering the valves and doing multiple operations simultaneously.
As experience comes you begin to do multiple operations simultaneously and the 'hoe will seem too slow. It actually will be slower as the pump power is spread across several functions. You can now speed up the engine and get faster cycle times. When you can "rake" the ground level toward you with the bucket teeth, you've gotten the feel of how to feather the valves and multiple valve operation down.
Always put down the stabalizer arms when digging. Even though I'm on a 3 pt, like you, I raise the back wheels of the tractor ever so slightly off the ground. I also put the front loader bucket edge down and take some weight off the front end with the loader. This will be necessary when digging in rocky soil to keep the bucking bronco put in one spot.
You can dig up and move immense boulders with the hoe. Bigger than you can pick up. Just dig around and clear the edges then use the bucket curl to work it up. My manual warns against using the side of the bucket and swing to move debris and rocks, you'll be tempted but try not to.
The greatest power of the hoe is in the bucket curl. And it's best applied closer to the tractor when the curl is comming up out of the hole, this pulls down the back end of the tractor against the outriggers and exerts great force. Running the curl at the arm extension will try to drag the tractor backwards--and it will succeed most of the time.
You will be tempted to operate the curl and boom or dipper simultaneously in hard to dig situations. This actually decreases the power available as the boom or dipper will stall and open the pressure relief valve, dumping hydraulic fluid and power. The bucket curl is the most powerful of the controls, use it alone in tough dig situations.
Things will likely get a lot smoother for you after 20 or so hours of back hoe time. I've seen 'hoe operators on big equipment, I've hired for my shop construction, get jerky on swing and boom movements. So, nobody is perfect. Have a good time with your new tools.
