Looking good!

85ºF is still a little warm, but supplemental co2 will help plants turn the additional heat energy into growth.

As to the "when" of harvest, I find that it varies greatly depending on a multitude of variables, key ones being strain or variety, lighting and nutrients.

The 90 day theory works if you are able to 12/12 by week 3 into week 4, then allow another 1 - 2 weeks for the plant to transition into bloom. So in theory, you're now at the 5 - 6 week point, if you have an Indica or Indica dominant strain, you may be able to finish the bloom in the next 6 weeks, putting you at 90 days.

I'd say as soon as your plants begin to show signs of bloom (not just declaring), your flowering period will fall into the 7 - 9 week window. Hard to tell from the pics now, but if they are aggressive bloomers, the mid to end of August is quite possible.

Then again, there is a rule of harvest that goes something like... "When you think your plants are ready to harvest, wait a week."