Would'uv, could'uv should'uv...
1. Color = Darker
2. Size = Bigger
3. Taps = More
4. Collar just a tad taller... used 7-1/4" stock. And now, with the insulation in place, and when they're on the hump, the cornies clear by a mere fraction of an inch with lines attached. On the lower level there's no problems at all.
5. I'd add a small trap door to the top, or to the side of the collar, to allow access to chilled glasses... My next one will have this... would also allow temp monitoring and maybe minor pressure adjustments without opening the complete lid and letting all the cool air escape.
Overall though, going with what I felt was a good size for my family room and 2 taps to start, with the intent to expand, hasn't been all that bad. In time I'm sure I'll wish more and more that I'd have done both to start, but we'll see.
Also.... I asked the same questions before building mine, so this thread outa' help a little: