If you can find a copy of The Autoharp Book by Becky Blackley, many of your questions will be answered. The book is a bit dated as it was published in 1983, so it does not take in to account the many improvements made in the autoharp by individual builders over the past 32 years. While there are not as many autoharp festivals as dulcimer festivals, they do exist. I highly recommend participating the Mountain Laurel Autoharp Gathering here in Pennsylvania. It takes place the last full week in June every year. Some dulcimer festivals offer a workshop or two on autoharp. MEG stands for Music Education Group and Oscar Schmidt sold a couple of models of autoharps with the MEG label on them. I think some of the first 21 chord harps were sold with the MEG label.
Ken
"The dulcimer sings a sweet song."