I rarely use a Towa as I never seem to get an accurate reading with Magnaglide bobbins, I think the magnet interferes with getting good reading. I test tension with every thread change be it a new bobbin, different color of same thread on top or completely different thread I test on the side and tweak as necessary. But I don't keep notes on it. I do track my time spent quilting and for that I have a large cork bulletin board mounted in my LA studio and with every new quilt I mark the date, if I changed the needle, needle size, start time and stop time. With every new quilt I tack a new sheet on top as I don't change needles with every single quilt and some quilt may require more than one needle if I am varying the thread type used on the quilt.