Another stupid noob!!! Flower question...

Just need some insight on my flowering baby girls.
ok so there 5 week flower now and i bin feeding them Ionic Bloom nutes
and bat guano, this is a soil grow btw. now they look pretty good but was wondering if at this point can i use any other nutes aswell to supersize these baby's haha...
also take a looksie at my pics, here are some close ups of them little white pistols, what signs do i look for to show they are ready for harvest, bare in mind i want max yield!!!

any thoughts are welcome, thanks!!

Hydro

and 1 more hehe...

Seriously, i need imput!!!

someone gotta have an oppinion on these!

your plants look really nice! i don't know much about nutrients, but i would wait on harvesting until about 50 to 75% of the pistils are orange. here's a link Harvesting Marijuana! When To Harvest Marijuana

any nutrient with a high phosphurus is good during flowering out of the three letters its the middle one N-P-K also a higher potassium number then nitrogen. also when flowering add calcium i added ostyer shells to my plants and they thanked me in the end