Hi, just adding to Cobalt's remark about the spacer ring, you could try using more than one i,e, shank material under the handle and handle material under that so you get a double contrast at the joint.
One of our older club members brought in a cane which he had made totally from save scrap from all hi sticks, it was made by cutting all the different coloured materials into 1 1/4 inch squares drilled at the center and threaded and glued onto a length of aluminium rod (presumably to keep weight down) inserted into the handle, this was all hand finished to produce a slightly tapered shank, sanded smooth and varnished. Made a good multicoloured shank stick.