Re: Guide size help for a 2/3wt 12'0''
Don't quote me on this as I am by no means a Spey/ Switch guru, but it seems to me that the old one guide per foot +1 doesn't hold true. The last 3 switch rods I have built have had fewer guides than the total rod length. I have been messing with 11' to 11'6 swtich rods and they have had 10 guides, including strippers.
They have also gone with about 4 to 5 of the same size guides on the end as in 3,3,3,3,3.
Sorry, I know I am no help
"Blessed is the fly fisher who's quiver contains grass, glass & graphite custom rods." Book of Rods 3:16