To continue, Kevin:   If you do tune your smaller guitar a full step high (above a 440-A) and you haven't had any structural problems with it, I'd say that either it's a very stoutly built instrument, in which case, due to its heavy construction, it could never reach its full potential as far as tone quality is concerned, or you have just been very lucky--so far.

A good friend of mine liked the sound of steel strings, but he also preferred the flat, classic width fingerboard. He bought a beautiful Martin classic (00-28-G, spruce soundboard, Brazilian rosewood back and sides, ebony fingerboard). He put steel strings on it!

Aware that it wasn't built for that, he used very light gauge steel strings and tuned the guitar a full step low. But even so--   All else being equal, steel strings exert about 2 1/2 times as much tension as nylon strings, and even with a lighter gauge string and tuning it low, over several months I watched in horror as stress lines (noticeable when light reflected on the soundboard of the guitar around the bridge) developed and gradually got worse.

My friend passed away, and someone else inherited the guitar. The fellow into whose possession it came, immediatly changed the strings, but the damage had already been done. The guitar will never sound anywhere near as good as it could have had it been treated properly.

I used to sit there apprehensively watching him play it and expecting it to explode at any time!

Don Firth