I have a Handi Quilter Avante (my second longarm - my first was a Voyager). I tend to stick with Glide and Magnifico (from Superior threads) now but have a boatload of cotton thread cones from Connecting threads as my Voyager really liked that thread. I still use the cotton when I need the color but you will find that the cotton threads tend to leave your machine really linty. I have also gotten really lazy - I also order prewound Glide bobbins !!
Bottom line - purchase several types and see what works for both you and your machine. Each machine is different .... Can you use your aurafil? Yes - as per the aurafil site - they recommend that you use 40 wt rather than 50 wt. Good luck and let us know how it worked out!!