Should be only a few more weeks I would think, but depends on how you like your meds. Some strains don't get super nuggy, so make sure your not waiting and waiting only for the trichomes to over-mature.
I prefer a upper,sativa ( clear/milky trichome ) high, it is much more heady, so I don't feel to bad about harvesting just a tad early.
Just make sure those trichomes concentrate up some more, and it should be ok without the magnifying glass.
Best of Luck with that!
RL