Mike,
You know my views on this
...
Its always a bit of a gamble when ordering blanks etc online, although going to someone like Meadow Fishery where you can phone up and speak to John, the rod builder is perhaps the safest way of doing it. Being able to jump in the car and actually handle the blanks/rods would be fantastic!!
What about a #3, a #5 and a #7. I think that range would cover 90% of the Trout anglers not only in this area, but most of the UK too. The difference between a 3 and a 4 or a 4 and a 5 is not really that great for most people, so I think you would be limiting your customer base????
With a 7 you are starting to get into Sea Trout and Salmon too, thus increasing that customer base even more.
Just a thought.