I continue to find feeding the correct amount of daily food a challenging task for a novice.
What exactly is a pinch? The guy who sold me ~20 fish, some relatively large, said 2 pinches twice a day. The guy who sold me a few guppies said the same thing. I see some saying all they can eat in a given period of time, usually 2-5 minutes. I would prefer something more precise, even if it meant using my gram sensitive scale for a while.
What do y‘all do?
I believe a pinch is just a tad over a smidgin.
The thing with feeding is that you're dealing with living things and so precision doesn't really come into it. This is why the 'time it takes' measurement is often used. That said, all of the food could be eaten within the 'prescribed' 5 minutes...and your substrate dwelling Corys still haven't eaten!
Alternatively, you could drop pellets in for the Corys, that yum it all up within the 5...but your hatchets up top are still hungry.
For me, feeding time is a fun activity and so I have no problem whatsoever paying close attention to each of my fish when grub's up.
I know which fish didn't appear to have eaten and which fish have eaten so much, not only have they stopped eating, but they're spitting out every other bit that they taste...just in case!
(Bulemic fish?)
So, for me, it's an art, picked up from years of experience.
At the back of my mind, I've always gor the spectre of over-feeding, looming large and leery and so tend to underfeed.
If the food I offer disappears quickly, I can feed some more or, more likely, will offer another feeding time later on. The next feed will see me deliberately trying to offer the food to those I know missed out last time. Sometimes, that involves me distracting the more assertive fish to the opposite end of the tank, leaving the less assertive to get fed.
As it happens, my current community doesn't appear to have any bullies or victims, so feeding is a lot easier.