I think a humanizing option that wouldn't be too hard to code, would be that within a variable number of refreshes, the refresh time changes to a greater span
Hypothetically settings might be:
Refresh 3-6 seconds
Every 15-30 refreshes, one new refresh may take between 3-8 seconds
Similar measures could be taken to blur the presence of a pattern, if you play with this idea of expanding time frames randomly


