I have a stabilizer leg in the back.
Feathering the grapple to prevent free feed of big piles allows the governor to keep up.
I get my pile on the tray, reset the grapple more towards the tips, throttle up to somewhere around 8-10/10, feed a big pile, slow the engine, throw in the stragglers, throttle down, go get my next pile. If there are two of us, we divide between machine-work and hand-work.
Stacking the pile right (lots of limbs curving overall the same way, butt ends within 1-1.5' of each other, somewhat feathered, not exactly even) or cutting to weaken crotches as needed on large pieces, is proper preparation. Then, I smile as the main feeds most of it.
Crushing the branches with the grapple may help.
If machine- forwarded, but not fed, like short branches, I drizzle then out of the grapple into the feed tray. Machine-smashed together is hard manual-separation.