Don't think only about what you have now or what you plan for next year. I have found that new and interesting products crop up all the time every year. They may be DMX or they may be pixels. What you should be thinking about here is your sequences. If you set up your sequence for 124 DMX and start your SS at 125 and then in the future you add a few more DMX channels you will have to redo all your sequences. With 4096 channels on the USB dongle, you have lots of room to spare. I leave the first 512 for DMX even though my DMX channel count dropped last year. But I had to go to an etherdongle and two active hubs in 2012. You may even leave blank pixelnet channels because it leave room for expansion and in my case I did not want my pixel tree to span two hubs so I had to start it at 4097 anyway. My point is that channels don't have to be densely packed at the beginning of a universe. You may find out that it was a bad choice in the future and the real penalty will come in redoing your existing sequences for a new layout with additional elements.
