Re: orvis float shooting head.
A 6wt shooting head on a 3wt rod will bend that thing down to the cork on a 40' cast, and could easily break the rod if you pick it up off the water wrong. A 3wt line generally just does not do well in the wind, especially with a large fly. Going up 3 line sizes will do nothing to give that rod the power to beat that wind. A 6wt rod with matching line will do much better.
The best way to get a rod to cast better in the wind is to learn how to double haul. Double hauling creates more line speed, and should help you shrink your loops as well. Tight loops beat the wind, not heavier lines. Its kinda like a golf ball versus a tennis ball. Even though a golf ball weighs half what a tennis ball does, if you tee up both and whack them with a driver, the golf ball is gonna go much farther because it is much more aerodynamic because of its size.
Doug can be of the most help on the casting front, and hopefully he will weigh in on this topic.