There is no discernible difference between single and 2-foot snakes guides to the extent that an average person could feel as far as I'm concerned. It's a cosmetic choice. I like the 2-footed.
The main arguments people make is that 2-foot guides weigh more. It's like holding 2 different size feathers in your hand. Would you be able to tell which one weighed more. I think not. The weight is so negligible as not to be noticed.
There is also an argument that says 2-foot guides stiffen the action of the rod. I'm sure that's true but I refer you back to the feather argument. Negligible.
Now, having said all of that you'll find endless number of people in agreement and disagreement with what I just wrote.
All I can say is that I've used both kinds of guides on the small amount (14) of rods I've built and I can't tell the difference.
This is just my opinion and I'm an amateur builder in every senseof the word.
Bruce