I've been real active in one of my leagues this Winter and just wrote owners' names in a list verticaly down a file folder. When they responded within 3-4 days to an email or offer, I wrote a "+" next to their name; after 3-4 days, a "-". Very rarely do I get a response of any kind after 3-4 days. I've found about 2/3 of the league to be pretty responsive, and from now on won't bother trying with the other 2/3.