I have good sandy, loam soil, and shallow-root trees, so they topple pretty easy, with the 4610 and FEL. I've pushed over spruce/fir/tamerack in the 10-12" range-30' high, and pines in the 8" range.
I start high on the tree and push, with minimal to no digging. Eventually the tree will fall over, and I lift up the root ball, sometimes from side to side, and carry the tree backwards with the toothbar. I then approach the tree from the side, and carry to a pile.
On a couple of the bigger trees, I first cut the root ball off, throwing it on a pile, then I wrapped a chain around the trunk of the tree, and dragged the tree out into the clearing to approach from the side and carry.
One thing to watch with this method though, you don't realize how heavy those trees are, and how strong the branches can be. I have a couple of dents on the grill of my tractor, even dented the push bar in the front when a couple of stiff roots caught me!
Have fun and watch your balance!
Jeff...U.P. of Michigan.