Congrats on your purchase. I believe the 1600P, the Viking Megaquilter, and the Pfaff Grandquilter 1200 are all the same machine. If you ever have questions about your machine be sure to search on all the machines because the answers are interchangeable.
My wife and I have the Pfaff. When we first started using it we had a lot of trouble, and I have posted several times about some of the problems we had and how we resolved them. If you have any specific questions, feel free to PM me, or you can search my posts about the quilter. We are able to use Maxi Lock polyester serger thread and Connecting Threads essential cotton. I have done all the quilting so far, and I have only used three patterns: a meander, a botanical-type pattern that "nests" into two rows, and a group of musical symbols that we drew ourselves. The purchased patterns that we have used came out of a book from Golden Threads
http://www.goldenthreads.com/shop/category/pantographs/ .
I hope you enjoy your new toy.
Darren