just to start a second skein there are several ways (the color question is already answered so I skip that)
you can just start the new skein and leave to ends to weave in.
depending on what you do you can find a great spot to do that weaving. If you sew things together, you best place that spot on a side that you sew in the end.
it the sides are very visible though you may want to have it further in. in your pattern I would put the spot somewhere to a devider of knit and purl because the fabric is not flat there, anyways and weaving will show the least.
you can also knit one or more stitches with both strands, if you think that that will be invisible enough (thick wool will really make this show, though). then you have less tight weaving to do in the end.
with real wool I have heard that some people felt the strings together and then do not weave in at all, of course. I unfortunately have never done it but listed it in my brain somewhere for when I will need to search for instruction :D