Bin too big?

I have my red wrigglers already in the mail en route to me, but I have done some research since I ordered them and I am pretty sure my bin is too large for the number of worms I have or just too big for a family of three to fill maybe. I’m making it from those big black and yellow bins you can find at Costco. I think they are 27 gallons? 1. Is there such a thing as too much bin for the number of worms you have? ( will I need to maybe start in half the bin?) 2. How do I know if I’m not feeding enough?