I absolutely love, love, love my HQ Sweet Sixteen. I easily use it FMQ with and without rulers and with and without the True Stitch stitch regulator attachment. You will love the HQ site, but especially the monthly 45-minutes or so videos showing all kinds of stuff you can do on the machine. They come out every second Thursday and stay on their site indefinitely. I promise you'll learn bunches of stuff. Visit their other areas as well.
As to rulers, I usually Google a general query and have often found rulers at a price less than some are offered by HQ.
To tap into and sign up for notices on Sweet Sixteen tutes, go to:
https://www.handiquilter.com/hq-live/