For those of us fishing very fast sink tips of some sort...especially in the Rivers  I would suggest that you never have a tippet longer than 4 feet attached to the end of your tip, under normal conditions. Of course there are exceptions to every rule...if the water flow is very slow it might be a good thing to lengthen that tippet accordingly.  Having a tapered leader attached to a fast sink tip is a total waste of money and effectiveness.
The use of Weighted Tube fly Bodies has proven to excell with good results ..this style of fishing and casting flies permits the fly fisher to swing relatively large flies with ease and in the Zone.