You can't enlarge the stippling. It would then be called meandering, I was told. I bought the 11000SE for the same reason, thinking I could quilt a whole quilt with it. You can but it will be one heavy quilted quilt when you're done. I thought that I could enlarge it - NOPE. I use lots of single line quilt patterns for quilting smaller items.
Are you sure you are using the most current and correct drivers and updates for the Horizon Link and the Acufil software. Most of those problems are computer related and not really about shooting it over to the machine from the laptop.
I saw a demo on the 15000 and the stitch composer. I'm not sure you can change it because it's basing the composed stitches on the new 9mm width of the foot and each box in the grid is approx. 1mm. Changing it to inches might be a problem.