what about maybe just trimming the top of the arrow shelf down say 3/8" then laminating on a 1/2" trim piece same colour as the vertical line- then sanding/filing down to the finished size- still giving you the required radius in the corner. would only give a cross on one side though- but no real loss in strength
or just do an inlay both sides, after rough shaping, of say 1/8" deep- shouldnt compromise strength
or do like kenny did on his last bow, and just have thin pads either side of the handle, and they could be made up with a glued in shape- much like a mosaic piece.
personally i like the shapes in riser no. 3- looks better balanced!!