I dug into this system because I wanted to determine the "weight" of the bamboo rod I am working on. It's pretty intriguing.
The 'boo rod came out at 8' 6", and a 3w with a slow action. I understand most bamboo rods are considered slow. To be more correct on the line weight, it should be a 100 grain line to fully load the rod with 30 ft of line out. If you routinely cast more line, the rod is effectively a lighter weight rod.
I checked some other blanks as well, then double checked my findings. The first rod I built came out spot on. The blank was supposed to be a fast 4W and it checked out as a 4W with a fast action. However, the Cabela's blank was supposed to be a moderate fast 4W and checked out as a moderate 3W that would benefit from one of the Scientific Angler lines that tend to be a half size heavy anyway. It isn't really a 4W at all.
I have 2 Batson Forcast blanks that are supposed to be 4 W, but the 2 pc checks out as a 5W and the 3 pc is a 3W.
To make a long story short, I am going to check out the TFO 5W I normally fish and like, and the Bass Pro Shops 6W I started with that feels clunky to cast, and see where they land. I may have the wrong line in that 6W.
Also, since I kept detailed notes on each blank, I am going to check them again after each rod is built to see if the double foot guides really do have a measurable effect.