What Arrow Rest To Get For My Recurve I Have A 69 Inch Bear Tamerlane Recurve From The Late 1960's Era. A 66 Inch String Seems Too Short.?

I have a 69 inch Bear Tamerlane recurve from the late 1960's era. A 66 inch string seems too short.? - what arrow rest to get for my recurve

From the back of the arrow rest of the chain is 12 1 / 4 inches. A 67 changes in the channel of 8 1 / 4. I can not do now, Fred Bear. How big chain is correct? I would not be able to get a chain of 64 inches on his bow. A series of 68 "hits my hand when shooting.