When you are free motion quilting you usually have your feed dogs down (but not always, sometimes you can control better if they aren't), so, either way, you control how long your basting stitch is going to be. You also control how fast you are going to go (you always have this in your control) so you can go down-up and stop, move your quilt sandwich a bit and go down-up a few inches away. I go pretty fast now (hope I'm not getting cocky!). ALWAYS start in the center and work out to the edges.
The trick is to be sure you are moving the entire sandwich and not just the top. That is why you need some pins in your sandwich before you begin machine basting. But, you can maneuver according to the size of your little quilt platform (my Janome 6600 is 9" to the right of the needle, 15" on the left of the needle, and the platform is 15" deep; so I have 24x15" of stable working platform around my needle. That is plenty of space to be able to keep the fabric smooth with your hands while you baste 3" lengths, pin to pin even if the pins are 10" apart.
I find myself lifting all 3 layers of the quilt (only near the needle) just a tiny bit to make sure it is smooth and not torqued or caught in any way. It becomes automatic, but first try it on a hot pad size and see how it works for you.
When you are done, or when you get wondering if it is going smoothly, put a bunch of stitches close (not on top of) to each other and take it out, turn it over and double check. I pretty much don't do that until I'm done now because I'm more sure than I was at first. If there is a pucker it takes only a moment to a minute to undo the stitches from the pucker to the outside edge or to the last good stitch because your stitches are so big. The you can resew, perhaps adding a pin or 2 as needed.
Having said all this I will admit that I have pretty bad arthritis and if I pin a lot (especially thru a 3 layer sandwich) I've used up my hands for the day and they'll hurt for several days. So, if this isn't a method used by many maybe its a "necessity is the mother of invention" sort of thing.
If you use double sided fusible fleece, check to make sure it all looks good on both sides (and it does) then you don't have to do any basting. I also have asthma and the sprays sort of scare me.
Hope this is clear enough. If not, ask questions and I'll try to answer soon. DON'T ask for pictures. I'm not smart enough to get one out of my mac and onto QB
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