The only (and last) batch of teeshirts we did had about 9,000 stitches-a really 100% covered area-and it puckered so bad on the test we had to do double 3 oz...might as well just sewn a patch and sewn that in place! But that was before the actifeed...so when I get bored some day I'll run a test and see. So far I'm having good results with the actifeed on cheap fleece blankets, sweats, workjackets, nylon jackets, and totes...I feel the actual sewn area is 'tighter' than without the actifeed, and we see either no bobbin at all in the back, or lighter material the bobbin is pulled right up through the front-no happy medium except hats and heavy jackets and totes! Weird...and our bobbins are lasting twice as long....using more thread instead. But it looks good, sews faster, and compared to before, almost no thread breaks. Roland