Aha, but it depends on how much you trust the shopkeeper.

You do a great blindfold test . . . .

You choose the best instrument in terms of comfort and sound . . .

They are placed in the order you chose (so you can then unmask and assess looks) . . .

Before you get the blindfold off, the salesman has 'snuck' the Martin HD35 to the head of the queue . . .

Simples   ;o)

That's probably how I ended up with two Martins