Cam Phasing

Is the off-set woodruff key for the camshaft itself an acceptable way to adjust the phasing? I have a good older chain and gears. I have read the typical horror stories of the new stuff. The damned keys start a $30. Another $100 plus gets me an adjustable crank sprocket and new chain and gears. I'd like to stick with my old stuff. I need to advance 4 degrees and ebay has the key to do it.
Edit: ebay