Flushing = starvation. Avoid it.
Don't overfeed.
Buds are about as big as they'll be, but they are gaining density and resin.
Extra light can help IF you were lacking to begin.
Really there's no magical solution. ;)
1/4" is too thick.
As lio lacidem stated, 115f.
Not sure if your water bath procedure is kosher as no temps were reported.
Older material can cause a budder like consistency due to decarboxylation and terpene loss that occured during cure.
Lets analyze.
Lets assume an incredible yield of 20% during extraction.
Lets assume .75 grams per watt.
A couple pretty big assumptions perhaps.
0.75 x 600 x 0.2 = 90 grams of rso.
Will that supply be what you need to get through between harvests?