If I knit on needles 1.5 mm smaller than recommended in pattern, for a ‘jacket’ which I’d prefer to wear as a cardigan, i.e. Slightly snugger fit, will I end up with something far too small.? . The overall size is said to be length 29" /width 74" using 5.5 mm needles for the body, and 6.5 mm needles for the rib. If I rib in 4mm and do the body in 5mm will there be an appreciable difference in size?