TWEEK,
I am sorry, it seems I have hijacked your thread. Did you get an answer that was useful?
I prefer double taper lines for all of my trout fishing. They can be reversed to get double life and I can live with the fact that they will not shoot as far as a weight forward line. Triangle taper lines are horrible on smallstreams they have an absurdly long front taper that will not give you enough weight to load a rod on smallstreams.
As to the line weights 2 and 3. A 3wt can do a good job much of the time, but there will be many situations where you will wish you had a 4wt. A 2wt is an absolute joy when you hook a small stream trout, however be warned that you will be very limited in what you can do. Forget big, wind resistant, or heavy flies.
Hope this helps and again sorry for getting off track.