hey 2dogs, I figure those eucalyptus are good ones for the bore cut method.
Yes, just below the backcut is best if there's lots of tension, but usually I am cutting straight out the back, or as I near the back of the cut I rotate around the tree and side swipe the strap with the tip, again just in one motion. For heavy leaners or where there is some other hazard where a concerted escape route is necessary I will pause and cut the strap from the back, and below it is the best for the reason 2dogs said.
For real heavy leaners, the tree can sit before you pull out to cut the strap- basswoods are bad about this, as are rotten trees, thus leaving an awfully large strap in sometimes an already tense situation. Just hit it hard with the full belly of your bar and dig dig dig my man, She'll break free and all will be ok.
If its a heavy leaner I may use a root for the strap, but avoid this otherwise as I don't like cutting them for the strap, again, they're prone to grabbing your chain (and saw).
I have had one awful barberchair with a bore cut. A large hollow as a gourd POS Beech cull. Faced it, bored from one side, left plenty of wood to be a strap- as soon as I bored in the other side POW she blew scared the hell out of me, about a 30' barberchair, the trunk just rested up there on top of the barberchair with the crown on the ground. Left it for the hunters to ponder. Only time though. FYI, beeches have been undesired since the beginning of time and they are usually large, heavy topped, and only have about a 2" rind of wood holding them up. Great den trees, otherwise worthless. I girdle em more than drop them these days, for wildlife and silviculture- makes too big of an unnecessary mess for the loggers to drop that big old top for an unmerch stick of wood.