[Ken43]

I have a 6 wt. Sage DSII. I am going fishing this weekend and would like to use a 10'sinktip. I don't have a 6 wt. sinktip, however, I have a 5 wt. and a 7 wt. which of those would be the best to use on a 6 wt. rod???
Would it be better to buy a 6 wt. line???

[Fish Bones]

First of all, let me make this perfectly clear, I usually advocate staying with the manufacturer's suggested line recommendations or, in the case of the heavier weights 6-9, underlining by one weight depending on the circumstances. Wait a minute… did I say underline? Yes I did. Doug Macnair opened my eyes to this concept. You see, as Doug says, it's in the amount of line you aerialize in making the cast. Consider for a moment that while you and I now know the weight in grains for the first 30-feet of our line, we don't know the weight of the remainder that typically includes the rest of the head, its rear taper, and the running line ... An interesting thought? It should be, because for every ten to fifteen feet we add to the initial 30 hanging in the air, we effectively add another line weight to the load carried by the rod. Said another way: a 5-weight line becomes the equivalent of a 6-weight when 40-feet of line are aerialized, a 7-weight with 60 to 65-feet in the air, etc. At some point, of course, our 5-weight rod will overload resulting in either a collapsed cast or worse, a broken rod. Then, as Doug would say, the Ancient Fishing Gods will be laughing.

So... You should be fine going with your 5wt line.

[Curtis]

You have received some sound advice there. But if I may chime in.

I am assuming you are going stillwater fishing? If not, disregard everything I say......

I personally would use the heavier line. When stillwater fishing you are so much closer to the waters surface that it can be problematic carrying too much line in the air. For this reason, I like to overline and therefore flex the rod quicker which helps to shoot line further for me. It is the shooting line where I get the longer reach instead of trying to carry 70 feet of line two feet above the waters surface. Just get about 30 feet out and then let her fly.

[Ken43]

I should have told you a little more, sorry. I will be casting out of my boat at a local lake. They have trout up to 10 lbs. The casts shouldn't be too far. Will be fishing mostly leach patterns.

[Curtis]

Then Steve's advice will suit you best. The only reason there would be for you to then use the seven weight is that the tip on it will sink faster then a five weight.

In sinking lines, they give you an average sinking rate. Say 4-8 inches per second. The difference is between line weights. A five weight line will sink slower then a seven weight line as there is more room to put extra sinking properties in a larger line weight.

Anyway, have a blast!