I just responded to your post in the Ask A Ninja Tech thread. Please call me at 877-646-5287 x309. I have some questions for you about what application this fitting is used in and some other questions about the application.
Rob, an update if you're still subbed to this thread. I bought the pump. The base threads were 1/4 bsp as you suspected, and I got a 1/4 bsp to 1/8 npt from mcmaster. Now I just need to stop by the local shop to get that fill whip!