Great thoughts, Tartan!
I was first planning on sewing the lines at every other pixel, which would make the lines 1.5" apart. Then I thought maybe every 3" to reduce the amount of lines that will be seen. Even with invisible thread, the quilting is more pronounced than I like. But you're right, maybe closer would be better.
I also was first planning on using my domestic machine, which has a generous throat space. My other thought is to rent longarm time (with a business I have done this with several times). I have to investigate how well that Gammill does with invisible thread. And yes, i would load it the long way and use channel locks.
Thanks so much!