My avatar tells part of the story. And yes, they're great! Quality parts!
One day per to build, and take Bob's advice and build one, test it, then if successful build the other. It's what I did, and during testing I found a couple unsoldered joints and one missing wire. The second one was a breeze.
I bought the solid state rectifier in addition to the tube rectifier, and KT88 tubes. Later I bought a set of KT120 tubes and those are what I use.
The sound is very "real" and lifelike! And Bob's a great guy!