Ive never trusted the offset keyways. The section width right at the corner where they offset the key gets fairly thin and shear strength has to suffer. Not to mention stress risers from the corners themselves. But, I do know it’s been done that way for years and years. Ive used the double roller billet set from summit and been very happy with them, lots of adjustment and they’re only $100.
Summit Racing SUM-G6603R-B Summit Racing™ Billet Steel Timing Sets | Summit Racing