There it is!  Thanks Phil!

I should have said that the strings I referenced above are the ones that come on a MMD (David McKinney's default strings).But you can order individual strings from juststrings.com in whatever gauges you like

 I use 14s with a 22 phosphor bronze bass for DAA tuning as my standard (experimenting with .01-at-a-time tweaks ups and down to optimize each instrument) on all dulcimers between 27 and 28 vsl, and I purchase my strings in bulk by diameter (much cheaper than prepackaged sets).  I'm really just curious about Dave's defaults.  I acquired my MMD second hand, and doubt that the strings are original as it is several years old.  Jan, I will try to contact the representative, and I appreciate the willingness of all to respond.

I use .012, .014, .024 on my Modern Mountain dulcimer. Here's a good place to order them.

http://prussiavalley.com/catalog/product_info.php?cPath=59_66&products_id=346

Or, if you have your old strings, just take it to a local music store and have them measure the gauges of strings used.  That way you get the exact gauge that was used.

William, you can order pre-packaged string sets from several different makers.  Martin and D'Addario make dulcimer specific sets which are available through Amazon.  You can also easily order sets from McSpadden and FolkCraft.

Be careful to order either  loop ends or ball ends depending on what your instrument needs.  Both are readily available.

There's nothing really magic about a MMD.  Strings are strings as we say.  Since you know the VSL, and know what tuning you want, you can use the Strothers String Gauge Calculator  to determine which strings will work.

 http://www.strothers.com/string_choice.htm

Since the calculator is notoriously "light" in its recommendations, add 2 to each recommendation -- instead of 12, use 14; instead of 22 use 24 gauge strings.  The MMD can certainly take the heavier gauges.

I suggest you go on the site and click on Contact Us to bring up the names of a couple people who distribute these dulcimers.  I know John Hawk and think he would be happy to answer any questions you might have--including string gauges!  His phone number is given, as well as his email contact information.

Can someone tell me the standard string diameters/"gauges" for Dave McKinney's Modern Mountain Dulcimers?  I have tried to contact MMD for info, but have gotten no response.