Try the original split tool. The command is SplitPolygonTool and SplitPolygonToolOptions. I keep these on my custom modeling shelf as I dislike the interactive split polgon tool.
As for the odd shading try unlocking the normals. This is under the normals tab. Hardening the normals can also fix odd shading artifacts but this will cause you to have to go through and resoften edges if you do not intend to smooth the model. Also turn off two-sided lighting to be sure you do not have flipped faces.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675