The end of the Polyleader terminates with a short section of monofilament. From this point you will want to add some more tippet material before tying on your fly. You can either create a loop in the monofilament of the Polyleader and then loop on tippet or you can use a blood knot or albright knot to join the two.
In terms of the length of tippet to add, keep in mind that you want your sinking Polyleader to pull the fly down in the water column. If you use too long a section of tippet then the Polyleader goes down and the fly stays up. Not good.
In general, 3 - 4 feet of tippet is ideal. It is long enough to separate the fly from the Polyleader but short enough to get the fly down.
good info, instead of buying a whole new fly line with a sinking tip I picked up a few poly leaders and was wondering about that. instead of a poly leader can you just use an OPST style sink tip?
Thank you for checking in with us. You can loop on a section of sinking line (sink tip) like that made by OPST or the CCT from Airflo. The biggest problem with adding those to the end of a floating single hand line is that they do not cast well and can be hard to turn over. This is because the fly line tapers down and meant to turn over traditional leaders. A polyleader are designed to be used in place of these tapered leaders and so they are quite a bit easier to cast.
Hopefully this helps.