Roy,
This is gonna sound self-serving for exotics, but I will post it anyway.
Making Private Reserve refills available to your pen customers is a great idea. If I EVER get to my retail pen site (which now has lions on the header, never changed the template), I will advertise the 9000 refill for customers. HOWEVER, I would GIVE AWAY more than I sell--I hope.
Advertise the two pack at its retail price, BUT if the customer orders a "pen for a friend", they get the two pack FREE!! So, your $70 gift is really only costing you $60.
You could build a really nice page to promote this concept. "Keep one refill, give the other to your friend" or "Share great writing with a friend", well, I don't have to tell YOU how to market, but for everyone else reading this--use the RETAIL price of Schmidt and Private Reserve to reduce the cost of your "new pen program".