I'm casting on two colors for the first time. I've made slip knots in both colors and have those on my needle. Now, do I start casting on using only one of the slip knots and cast on the required number of stitches? If I do this I'll end up with all one color stitches and a lonely (other color) slip knot at the end. Or, do I cast on alternating between the colors? The cuff of the hat I will be knitting is only one color for about 1", so I'm not sure why I need to cast on both colors rather than just introduce the contrasting color when it's needed, but the pattern says use "two-strand cast-on using two colors" so I'm trying to 'trust the pattern!" Please help if you can...thanks!