I've come to believe D tuning is the only way to go with sopranos...the string tension is higher...and often it seems to help the intonation troubles i've had with some less than wonderful sopranos...i actually fiddle with key alot, my mainland tenor is typically tunes to A (two steps down) and my sopranino is tuned to E two steps up...With the tenor is still maintains tolerable string tension...and the sopranino bridge has yet to rip off (yet)
I agree that the sound is twangier...i really love the nearly banjo like sound the sopranino tuned up 2 steps produces...
I've always thought the string tension is much too low for most strings and sopranos when tuned to GCEA giving an almost rubberband like flop to the strings....
For people concered about learning a whole knew set of cords...i say don't worry about it. when you read off a chord sheet for a song you can still play the same thing, as long as you arn't playing along with anyone, you're still strumming the same chords (the shapes stay the same of course) they are just D G A instead of C F G
because i have a fairly good sized uke collection ( 10) I use this technique as if it were a capo...A song too high for me to sing as written BOOM grab the tenor tuned down two steps....for a song too low...the sopranino is ready to go two steps higher *and 4 whole steps higher than the sopranino, thats half an octave!* it really adds alot of versitility in tone. The normally mellow tenor its even warmer and sweeter...and the spritely sopranino really dances with a higher string tension....anyway just some thoughts DON"T LET YOURSELF GET STUCK IN GCEA! you can change the tone of your uke in 30 seconds and without trying a new set of strings