When should I start to pick?

[Weezard]

hm... about a month and all purpose plant light

At full zoom I see no amber trichs.
It looks like you have a few more weeks to wait.
To be sure though, I recommend that you buy or borrow a cheap microscope.
(Radio Shack, about 10 bucks)
Use it to take a close look at the trichs.
When they are "mostly coudy" with sprinkling of amber it's a nice mix of head high and couch-lock.
In short:
More light and more waiting is advised.

Aloha
Weezard