question how long after the start of flower will it be till I need to harvest?
Depends on the strain @Peterpenguin , around 60 days for flower give or take.
Those look to have a bit of sativa in their genetics…could be as long as 12 weeks or more, but probably less. Very general rule of thumb is once the pistils start turning from white to red, you have a few weeks remaining, and you should start watching the trichomes for desired maturity. Wherever the seeds came from should be able to provide an estimate on flowering time. Or if you know the strain, you can do some Google Fu and get a pretty good idea. They look pretty good, and with the training you’re doing, they should really fatten up nicely. Nice work so far, be patient!