Derek,
>>What does tibbanikkamo mean? Is is something like "keenly going on
(toward his goal)"?<<
Tibbanikkamo means '(of) strong or ardent persistence' or similar
translations. The PED has the background of the word tibba wrong. It is
comparable with the Sanskrit 'tiivra' which comes from the root 'tu' (which
I don't believe the Pali has any other words from). The commentary gives
these meaning for tibbanikkamo: da.lhaviiriyo, thiraparakkamo.
>>There seems to be a metrical peculiarity in the second line -- is
brahmacariyassa scanned as brahmacaryassa here?<<
Most probably yes. Words such as cariya, ariya, etc. are scanned as carya,
arya.
Sean