Re: String gauges for 5ths on Alto and 10 String
OK, I've done a bit more digging and reverse-engineered the following (from a response by Emmett to an old email I sent him) with respect to pitches of melody strings:
A. Because of bass scale string tension, the highest pitch on the 10 string stick is D (maybe Eb at most).
B. The corresponding highest pitch on the Alto is G.
Unless someone more knowledgeable than me says otherwise, I'm going to assume that it's meaningful (in terms of string tension) to tune melody strings 2 through 5 down from there in 4ths (i.e. so that they ascend in 5ths), and order strings from SE accordingly.