1. All the albums I mentioned I used a fold down mix, except for Piper, which has a combination of fold downs ("Matilda Mother", "The Gnome"), actual mono mixes ("Chapter 24, "The Scarecrow"), laying bits of the stereo mix on top of the mono ("Lucifer Sam", "Pow R. Toc H.") or even splicing fold downs and original mono ("Interstellar Overdrive", "Bike"). I haven't been able to find a good combination of "Astronomy Domine", "Flaming" and "Take Up Thy Stehoscope And Walk", but I will keep trying.

2. I have the Rhino release of the Grateful Dead's debut, and it's in stereo. About the worst that can be said about the fold down for that is that the instruments are sometimes drowned out by the signing or by Jerry Garcia's guitar. It's not that severe, but I wish they did a better job recording Pigpen's organ. A similar case could be made for Robbie's guitar in "Light My Fire".