From a non-professional, just my experience:
On several GL1000s I have found that you need to go back-and-forth between gap and timing due to tollerances and wear. Timing is of course most important, but gap effects dwell (time the coils have to build stored energy that they release when the points open). "In the day", mechanics used a dwell meter to adjust point gap. Today the meters are hard to find and few mechanics know what they are let alone how they are used. As electronics improved in the 60's and 70's, gap became the criteria as the coils improved to permit a wide range of dwells. I seem to remember several gurus recommending setting the gap at maximum in the range, which would decrease dwell. There is usually supposed to be a mark on the points cam indicating where the high point is. Mine have been hard to find. Make sure the points cam is smooth, not rusted or gouged. And, make sure the advance springs have returned it to minimum advance.