Nate makes a great point- just because the entire lengthh of the vsl between nut and bridge is a substantial 2.5" longer, that doesn't mean the chord stretches for your fingers will be 2.5" longer. The distance between frets you are using in a chord will be a modest amount longer.
Do you know anyone with a regular length dulcimer you can try out? ('regular' usually meaning somewhere between 26 - 28.5" vsl)
I have found that very often beginner players are solidly convinced they will not be able to make stretches that later on they discover are actually do-able.
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