Why can't you wind several bobbins before quilting? Seems like you ought to be able to do that, but I don't design sewing machines, so who knows?

on my Gammill long arm, the on-board winder winds as you sew, so you can't 'pre-wind' a bunch of them. I have a separate winder with my machine and love being able to wind extras ahead of time. And I almost always buy 2 cones of thread so that one is on the winder and one on the machine.

I would suggest a bobbin winder you can adjust. I had terrible on and off again tension and had wonderful service from my long arm dealer. We could not locate the source of my tension issues UNTIL my bobbin winder died. I got it with my long arm and never really liked it. It was not adjustable and I could not service it. I bought a gently used winder from an online friend. It is not pretty but winds the loveliest bobbins. No tension issues.

I have the bobbin winder that came with my Babylock Tiara (which is made by Handi Quilter, btw). It’s easily one of the more expensive winders on the market, and it’s not one I’d recommend as it gives me fits.

I purchased a Gammill three days ago, but while researching Longarms extensively, also researched bobbin winders and ordered the Innova bobbin winder online. It’s half the price of the HQ winder and from everything I can tell, is several times better.

Did you get the regular bobbin winder or the industrial one from Innovative?
I’m strongly considering buying one.

I got an industrial (to me at least!) bobbin winder thrown in when my friend and I went halves on a very basic Babylock Jewel long-arm. This uses L bobbins, but I have also wound class 15 bobbins on it, don't know if it would work on M bobbins. I don't see any reason why it wouldn't though.