First teaching wine tasting help

So I am planning a little get together and plan on doing a teaching wine tasting. I was planning on doing a comparison of New world vs old world wines. I have some Napa Cabs to compare to Left Bank Bordeaux. I have some California Pinot, would prefer Oregon but don't have any left from my favorite Williamette Valley Wineries, that I will compare to a value option from Burgundy. The final is a toss up. So I have a few Rioja bottles that I could find some New world Tempranillo. Or I really love CdP wines so I could do a comparison of CdP to a new world GSM blend.

Does anyone have suggestions on wines or if I should go in a different direction. This tasting is for like 6-8 people and my wife and I love wine so we are fine drinking some left over wine for a couple days.