I have done this many times, but couldn't find the reference on where i got it as its been a few years since i retied it. Just loop the 19-strand through the swivel and over it like a half hitch. Then up the line about an inch or two, tie a single over hand (plain knot) with the main line and the tag line together.
here is a vid of a guy doing it i did find, which is exactly as i described. Really easy knot to tie, plus i have never broke one off.
https://www.youtube.com/watch?v=lPR1lzOyLIgthis line is a must have for dispy's. If you get a chance, run the weighted steel with 19-strand (for non-dipsy applications). Its a killer on my boat and one of my main rods all year long as a straight line out the back. This stuff gets deep. 50' of mono backer / 1000 ' of 19-strand then 200' of weight steel. Goes 44' with all weighted steel out, plus another 40 with another 200 of 19-strand out.