I have a simple scarf pattern that says to knit w/ two strands of the same yarn using very large needles (size 19, I think). I think the reasoning behind this is that project will be a quick finish. Personally, I’d rather have it take longer and not have to worry about getting tangled w/ two strands. Is there some formula for what size needles to use if I’m going to use 1 strand instead of 2? Or, is knitting w/ 2 strands just as easy as using 1 and I should just follow the pattern?