I've had really good results with my "Myer's Pick up" The owner asked to put me on his web site. I figure it couldn't hurt so here's the blurb. I bought it from amazon for about 130 dollars. I took off the "suction" cup because it just doesn't stay on the dulcimer. Once it was removed It lays flat. I've successfully used "command Strips" and they have not hurt my dulcimers. Although once I'm done recording with the pickup I immediately remove it. Don't want to take any chances!!
Here's the link if you want to hear it in action. By the way I'm not "promoting" him I just use it and think it's a good product. The owner is also very helpful and when I struggled to remove the suction cup he actually called me on the phone to walk me through it. It was a little tricky with the screws and eventually my husband had to use a special tool but off it came!
Take care and good luck!
Maria