I'm not a builder ( yet ) but I restored one a couple years ago, as far as sandin go's I took it down just enuff to get the old finish removed and then didnt sand it aggresively, I was afraid I mite damage somthin.
I finished it with a satin polyurethane ( about 3 coats) it turned out purty good to me, the wood grain shows up good and the finish aint real glossy, just enuff to look good but not enuff to make it flashy.