String guage depends on your preferred tuning. Folks who tend to live with a DAA (or other I-V-V tuning) tend to go for slightly heavier melody strings that the DAD (I-V-I) crowd. On the other hand, I tend to keep DAA style strings on my McSpadden and risk breaking when I tune up to DAD rather than flopping when tuning down to DAA with DAD strings. My sized .012's on the three upper strings, .022 or .023 on the bass -- this is for a McSpadden, but should give you a ballpark figure. The only other consideration is ball or loop end, and that depends on your instrument.

As for strumming, again it depends. When I'm playing gentle songs, I tend to strum away from my body: treble to bass. However, when I'm playing fast fiddle tunes, I tend to strum bass to treble to emphasise the downbeat. This works particularly well with jigs and other tunes with a lot of triplets, I strum the first note of the trio hard, and grab the other two with hammers, pulls or slides. Really gets that bass humming.

One of the joys of the dulcimer is that in many ways it is an evolving instrument with no fixed technique. You do what you like and follow your ears....and don't forget to try different tunings. DAC is haunting for minor tunes, DGD for fiddle tunes in G...the list goes on.