ok, i'm making my own counterflow chiller, folowing this design: http://www.homebrewtalk.com/wiki/index.php/How_to_make_a_Counter_Flow_Chiller
everything is set, except for the rubber hose... i'm having trouble finding a 5/8'' one. I found a 1/2'', though, and although it's smaller in diameter than the one in the design, it appears to still leave enough room for the water to run through over the copper tubing. So, my question is: can I use this one or should I keep looking? Is there a relation between the inner diameter of the rubber hose and cooling efficiency? And in this case, if I bought a giant-sized (let's say, 1''), would it chill the wort faster?