Wally, glad you are willing to dive and in take the bull by the horns after waiting so long. I would recommend (if you haven't already) that you review the Pilot materials at vatsim.net on how to fly on the network (I do not mean to imply in any way that you seem to need them, just most people forget to look over them when they start and can miss quite a bit of useful information. You will find most ARTCCs have the best staffing between 1800 (6pm) and 2200 (10pm) in their local time, with far more ATC coverage on the weekends than through the week. For instance, the best time to catch NY, Atlanta, Miami, etc would probably be in the evening (Eastern Time). You can use a program like VATSPY, ServInfo, etc, or go to
http://vattastic.com/ to see the information in your web browser. If you let us know what time you are trying to find ATC (and in what time zone you are in) more specific information can probably be given.