Paul, Niccolo Alessi can go as simple as you’d like. Here is a set he made for our 100th guitar, built to commemorate my Granddad’s little parlor instrument:
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Simple, rectangular nickel silver plates, chosen to replicate the originals. Keep in mind the extra strength that a 3-on plate tuner offers to a slot head. Those exterior walls are thin, and fragile as a consequence, and the added strength of the metal plate is a real bonus in this regard.