Can you get a pullout extension for that crane? You should have an angled pullout extension, especially since the crane has no fly-jib.
If you need a Mecanil grapplesaw from someone that will actually support you, give me a call.
That chart is showing the boom straight out horizontal... the jib is rated for much more than that. Attached is a PM 100 load diagram, same as @CanaryBoss's boom configuration I believe.
*edit*
Just checked out the operators manual, looks like the jib hook point is rated for 11,000 lbs
This is what Steve is talking about. https://www.weighingreview.com/article/arborist-adds-sp-load-pin-to-tree-felling-toolkit and https://www.straightpoint.com/media-articles/589-straightpoint-load-cell-in-tree-felling-application.html
It tells you the actual weights on the end of the boom in...
I would suggest checking out Chad's knuckleboom in person and talk with him (someone that actually works around the same types of trees as you and actually runs it, and has a stick boom to compare)