Keep increasing the offer to appeal that the target consumer is getting a deal.
I took a class in direct marketing in college. This was one of the commandments. Also give the contact method at least three times.
There is no 8oz, or 16oz im sure. Just makes the customer think he is getting a huge deal. Add the small bottle, the pocket packs, and I LOVED them showing the clip of the 20 bottles that they can make out of one bottle of WC.