Those beans will not be as fast as a drink or a gel. Your stomach has to churn it up, which takes more time than a liquid carb. (Really, one of the fastest things you can use is Gatorade Prime. But that comes in a 23 gram pouch, which you might not need all the time.)
3 grams can help, but…if you are dropping quickly, it might not do much to help.
And yes, a quickly dropping BG will need more carbs to stop it in time than a slowly dropping one.
It’s like this - 10 grams might be enough to stop the drop and level you out. But 20 grams will stop it faster. But then you have a few extra carbs you did not need.
So if you have time - you are still not very low or it is a slower drop - you can take just what you and it will work fine. The jelly beans can help with that. Or 1/2 a gel pack, or whatever.
But if you do not have time - it is falling quickly or you are already in the tank - do not screw around with trying to take the exact right amount. Take more than you need, that will turn you around quicker.
And then when you get enough practice, you can actually be low, take a big dose of carbs, and take just a small bit of insulin at the same time to cover the carbs that are “too much”. That will fix you faster than anything, I promise.
I heard once of a guy who was in his 50’s and took carbs and insulin at the beginning of a run. You can do that too.
Does that answer your question that you were not sure if you were asking?