My feeders get filled at least once a week as they are emptied by the hummers by then. Is it time to stop feeding them as they prepare to leave for the winter?

Shamefully,I do add some red coloring when I make the solution for the feeders (1:4 ... is that too weak? How strong can I make it that is good for them?)only as it is easier for me to tell when at a distance if the feeders have any red solution in them yet or are empty? I rarely see more than one at the feeders as if another one comes close the first one 'chatters' & chases it off ... very inhospitable don't you think?! They waste more energy chasing each other from the feeders! I have noticed that when the feeders are empty, a hummer will often come up to the window, look in & hover ... like telling me I need to get busy & make more! As for which they prefer: a sit-downfeeder or one where they have to hover: I notice they always prefer to 'sit down at the table to eat' at mine!They can relax & enjoy their meal without expanding any energy. Silly to see a sparrow try gymnastics trying to sip from the feeders as they wind up tipping it... & then solution splashes out on the ground!