Bushwalk Australia

Would anybody like to give an opinion about epicormic bud regrowth speed in a Ficifolia?
We lost all the top of the Western Australian red flowering gum in the back yard this year.
My own fault too. Allowed our neighbor to trim an overhanging branch but neglected to trim it flush with the main and paint it with bitumen so naturally the beetles laid eggs there. Only took a few months for the grubs to ringbark the mature tree
Today I noticed the first of the buds breaking though the bark about 600mm from the ground
We will leave the dead trunk standing and bolt nesting boxes to it

A second epicormic bud has burst through. I just spent a half hour cleaning away all the spring growth of the damned kikuyu grass, stuff acts as growth inhibitor and I want this tree to come back. Locally it is an important food tree for the Rainbow Lorikeets when the Yellow Box next door isn't flowering