Was there a standard design for the whirle range. The reason I ask is that I've got a banjo mandolin, banjolin or what, That has an 11inch pot, smaller tonering and resonator. The only pictures I've seen of them Have been backless without the tone ring but I have seen a windsor popular with an identical body to mine. I know nothing about banjo's (or much else) and wondered if it is a marriage of bits, everything seems to be original.