Choosing to harvest with a lack of experience is difficult. You simply have to go through it to get better at it. Your preferences may not be the same as the next person as far as how much ripeness you want.
trichomes, bud density and pistil coloration/visible length are 3 things you can observe and use to create consistency in when you harvest. Not all plants progress the same. Sometimes buds get fully fat/ripe and then you have to wait 7-14 days for any amber to show up etc... others are showing maber trichomes before the buds fully fatten. So, you'll need to learn how to handle each of those contexts on your own. Take notes; be systematic. That way you can try something different and compare to what you did before with some confidence.
Hairs look long, which indicates some plumping of calyxes remains... but some phenos have longer hairs -- see what i mean? Use other observations to help make the decision. Did the fan turn them rusty-colored prematurely? Unless the trichomes are predominantly amber, i'd let these fatten more.
------------ re: harvest flushingThis plant doesn't look overly lush or crazy overfed...
Buds don't store excess minerals anyway. That's not their physiology. do your balls or uterus store lipids? No, your adipose tissue does that. Plants may not be as complicated, but they still have cell differentiation.
if any adverse nutrient concnetrations were provided that could influence flower growth, it happend while the flower was constructed and there is no changing that, now. i don't think that is a concern here, for what it is worth.
Some damage is expected at end of life. Some plants turn darker or red or purple etc. some can remain more pristine than others. think of someone that looks 70 at 50 and someone that look 50 at 70, lol. These are not binary contexts.. there's a spectrum of possibilities.
You should always correct deficiencies and toxicities as best you can. but there's no changing flower grown weeks ago. That ship sailed. Tests show that the water you give the last 10-14 does has no impact on mineral content of flower... not an opinion. Quantitative, empircal evidence proves it. If the leaves are not strong enough to provide, one could easily extrapolate why this could be a negative effect, too... can't construct molecules if the building blocks don't exist... mass is not manifested out of "the ether."