I'll add a sort of different approach to this.

Since the idea is to have the tip sink, I always use a section of heavy fluorocarbon leader to make the loop. Flourocarbon is denser than regular mono, thus it sinks better and won't cause a belly in the sinking tip section. Then, I use a palomar knot to attach a piece of tippet to that. I don't use a 'leader', tapered or otherwise, on sinking/sink tip fly lines. Length of tippet varies with presentations, but usually only a couple of feet is needed. Again, I use fluorocarbon tippet, because it sinks the best.

Good Luck!

Buddy