I wish I had better news for you, but...
It's probable that someone sold you the wrong base for the WI (which is sadly common).
As you're probably aware, all Wapak Indian Head items are highly collectible. They are also not nearly as common as a Griswold or Wagner item. This means that it will be very difficult, time-consuming, and costly to acquire the base for your WI.
Additionally... I don't think that the correct base has any markings or indicators on it to inform the owner what brand, type, and size it is. This makes is nearly impossible for you to acquire the correct base.
Your best chance is to (miraculously) find someone who has the same WI as yours in a complete set, but has broken paddles. One of you would be able to buy parts from the other to merge the parts into a matching set.
NOTE: I am a moderate cast iron WI collector. I have the low base for a Wapak Indian head WI, but it's not the same type or size as yours. Mine is the usual size-8, and it's the kind that has a metal ball on the handles. Both of my paddles are broken, which was known when I acquired them (I got the entire set for free). I search for matching paddles at an affordable price. When I find them, I'll merge them with my base have a nice set (if all goes well).
