I have a couple of short scale (24") acoustics, namely a Gretch cowboy and a Yammie APXt travel guitar. I generally play 12's, but I've hear talk that you need heavy strings to drive a short scale to sound good? Since these two guitars are ultimately destined to be played by my 11 year old, I actually would prefer to maybe go even lighter, say 11's. Waddya think.?