I am rebuildung an autoharp, my first attempt, and need some advice regarding string selection.

After stripping down the body and removing all of the deteriorating felts and the rusty strings, I haave cleaned up the body, which is in excellent condition, cleaned up and replaced the tuning pegs, and am now restringing. I haven't even thought about cutting the new felts yet.

I am restringing the harp Ionian on D, with a couple of accidentals added to make certain chords, and the entire middle octave will be double-strung. So ordering a standard autoharp string set is not an option.

I've been getting the strings from my friendly neighborhood guitar shop, 59 cents a pop for the plain strings, as opposed to $3 plus shipping for 'dedicated' autoharp strings available from d'Aigle and others online. And of course, the thinner guitar strings are long enough to make 2 or 3 top-end autoharp strings.

So far I have strung positions 1-14 (D2 to D4) with wound strings (.090 to .026) and positions 22-36 (A4 to D6) with plain strings (.020 to .013). I've added a small auxiliary bridge to 36 in order to get it up to D.

So my question regards the 7 positions so far unstrung (15-21). These call for string diameters of .022 to .024. It is hard to find plain guitar strings of these diameters in stores. I've called every store in town.

D'Addario makes plain strings up to .022, Ernie Ball up to .024, and ghs all the way up to .026, but music stores tend not to stock these because there is very little demand.

Should I finish my restringing with .022 and .024 wound strings or hold out for the plain strings at this thickness? What, if anything, would be the difference in the sound?

Any other advice of a general nature would also be appreciated. One learns by doing.