About the Clasped Weft Join
So why is the clasped weft join so great? Because it weaves in the ends as you’re working. Because of how you hold your two yarn ends and knit them into the few stitches before and after the join, you are already securing the ends of the yarn. And this means that when you’re all done, you just go along and trim the ends.
Getting Things to Line Up
The biggest challenge I faced was figuring out how much space to give myself so the yarn join matched where the stripes end and begin. This meant a lot of adjusting the length of the yarn on either end of the join. I hate to say it, but the only solution to this one is practice. You need to give yourself several opportunities to see how much yarn each stitch uses up.
Controlling Tension
I also dealt with differences in tension between the actual working yarn and the tail. In my first version of the socks, the tail was significantly looser. I tried solving that problem by pulling the tails tight. That created a weirdly puckered look, though. You'll also need to practice to get the tension right.