The hardest part of doing the rod is putting the guides on in a straight line on the side oposite the rod's spine.
That said, I made the mistake of once making a rod with a cheaper blank than the manufacturer whose rod action I liked. Remember it takes just as long to turn a blank you won't like the action of into a fisnished rod as it does one that you do like.
The first rod I built was on a Fenwick HMG blank back in 1975. These were very expensive blanks at the time but they had the action I desired so I bit the bullet and spent the money. I was not unhappy with the resultant rod and fished it for 6 years until it was stolen. Then I made the mistake of getting a cheaper blacnk, heck I got two of them for the price of a more expensive one. The rods were OK, but I never really liked their actions, too slow for me. This was really false economy. I ended up giving them away the next year and bought two G.Loomis blanks because I liked their actions.
I never made that mistake again. Pac Bay blanks are OK but they do not make a rod with an action like the Sage rods you mentioned as favorites. They are even a little slower that the Loomis GL3.