Is Re-Fretting Possible Without Damage?

Looking down my dulcimers (my third one) fretboard I find a slight warp going downward not side to side.  My measurement indicates a rough depth of 3/16” from north to south. My plan is to remove strings, nut, bridge, tuners and frets of course and then flat sanding the entire fretboard to level with a of 3” aluminum square tubing using Im guessing 150 grit sand paper as a starter and then finishing  accordingly. I realize I would have to deepen the original fret cuts on both north and south ends to accommodate the re-fretting that’s not a problem. The problem is, and I know you all know where this is going, comes when retapping the new frets into place (a real danger zone) on top of the dulcimer.. it’s impossible to support underneath the board Sooooo, I’m thinking support from side to side.   

I’m considering making a jig with 2X4” lumber (it’s cheap) making two squares both a inch wider than the widest part of my dulcimer and approximately 6” high, at least taller than my dulcimer. These would act like a square hangers that the instrument would be suspended from if you will.  On one side of this hanger a 3/4”x4” wide or so piece of wood with cork or some other type protective material perhaps rubber, would be attached and it would extend out and pressed up against one side of the fretboard without touching the sides, the other would would have a similar piece except pressed up against the opposite side with a adjustable 1/2”x6” bolt to act as a locking device or vice. imagine the fretboard being tightly sandwiched in-between these two hangers and the body of the dulcimer suspended and then taping in the frets.. 

Will it work without damaging the goods I think so but it’s just an idea at this point..  If any one has successfully re-fretted I would love to see or hear of your method of madness on how, and if any of you have any other ideas on my dilemma to share it would be much appreciated. I need to do something I’ve already made my share of kindling.