I had some time to mess with this over the weekend and, just to make sure the number of little zits decreased, I first increased the refresh time from 10 sec to 90. No sagging and many fewer zits.
Next, I disabled the refresh altogether and carefully watched a print and saw no sagging. No zits at all now.
In the end, I opted for making a little "sling" out of a garbage bag tie that I put around the servo arm after bed leveling is complete and it acts as a safety in case there is a sag; however, I've now completed four 4-hour prints and the arm has remained rock-solid EXCEPT one time when some static electricity from my finger to the printer frame caused it to move downward slightly.
I've been thinking about getting some grounding wired into this thing because the static also scrambled my LCD display a time or two. It's really dry where I live.
I know Marty has this problem too because more than half the prints furnished in my kit have the same little zits on them...