Use this site for the timers
http://www.garlandtools.org/bell/
An easy way to narrow what you want down is to select Patch 4.0, select Botany and Miner for classes, then for type pick Ephemeral.
You will get something that looks like this, but with the map out... which should tell you where to go for the ephemeral nodes.
https://i.imgur.com/AIrgRuG.png
Assuming you have a lvl 70 Botanist and lvl 70 Miner with BiS/ Yellow Scrip gear, with the aid if food ( use Nomad Meat Pie from Reunion in Azim Steppe ), you should have over 600 GP and stats to do a proper aetherial reduction farm.
With collectability on select the highest level item ( Yanxian Verbena for BOT or Yanxian Soil for MIN )
With 600 GP use this rotation : Single Mind - Utmost Cauction - Instinctual Appraisal - Instinctual Appraisal - Instinctual Appraisal
From here, if you have at least 360 collectability, use Single Mind then a final Instinctual Appraisal.
If you have less than 360 use Discerning Eye then Instinctual Appraisal. IMO I find it easier to use have a macro that does Single Mind - Utmost Cauction - Instinctual Appraisal - Instinctual Appraisal - Instinctual Appraisal - Single Mind - Instinctual Appraisal at all times since it is mindless farming but to each their own. Whatever gives you more aethersand overall is debatable but I find my rotation works with minimal fuss.
When I start proper I will first start off by doing a red gathering scrip run so I can buy a ton of Cordials that should last me for hours.
From there, assuming you are starting right off the bat from 600 GP, you go over to the node and use the collectability rotation and harvest what you get. Pop the cordial then go to the 3 nearest nodes to reset it then farm again. While the cordial is on cooldown, if you're still regening your GP you can refresh the ephemeral node again until you have a +1 or +2 to gathering attempt. I usually try once or twice before I just gather whatever I find. This should put you at near 0 GP with a few minutes left to go on the cordial. From then onward you keep going around and refreshing the same ephemeral node until you get +1s or +2s or once you have enough GP to make another attempt, popping the cordials as soon as they comes up.
Hope this makes sense/ helps!