Xlyphone - you can cut wood or metal to length, support the notes on string - I am sure there is a correct position at a null 1/4 in from the ends.

Tuning with a hacksaw - keep the blade for tuning the banjo.

Certain metals (springy or hard) do better than (say) copper. Woods- similar, hardwoods well seasoned. Thicknes and witdh - I have no idea but one look at one in a shop would tell you.