I have an APQS and I bought a couple of extra bobbin cases for my longarm. I usually use So Fine in the bobbin and have one bobbin case adjusted for that. I have the other two adjusted for OMNI and for bottom line as I sometimes use them. I could adjust the bobbin tension when I change bobbin threads but it is just so much easier to switch the bobbin cases and usually then, I just have to adjust the top tension a bit. I do not have a Towa gauge and actually never saw the need for one.