Please don't use pressed air on the machine. It can drive the lint and dust deeper into the machine and also it can do damage because after a while it gets really cold. I use a small vacum on mine. I got the attachments at Julia's Needles Designs for about $10. Just don't use pressed air.

Having two machines is a good idea for the avid sewer/quilter. If one goes down and has to spend time in the shop the other one allows you to keep working on your project. Having one with light thread and the other with dark thread is an excellent idea. I noticed all the space under your table. Have you tried placing some of those plastic storage drawers under the table, perhaps in the center, for things you need to use while using your machines. I have the small drawers that I keep machine needles, pressure feet, scissors, bobbins, etc. in. Now I don't have to leave my machine to access these. Sewing time is precious and having things at my finger tips allows me to change bobbins, needles pressure feet in just a few seconds.