I love my Tirara 1, which is (I understand) the same as the older model Sweet 16 Handi Quilter. Mine is a 2014. It had very few stitches on it and came with the regulator which I never use. I got a great deal for it, less than 1/2 price with a bunch of rulers and books.
To change threads, snip your old thread at the spool but don't take the thread out. Put your new spool on and knot your new thread to the old thread and just pull the old/new thread through all the guides until you get to the needle. That way you don't have to remember how to re-thread it every time you change colours.
For tension, look at Jamie Wallen's tension video on YouTube. Invaluable.
You're going to love it.
Watson