The smallest pin you can get away with is a function of the viscosity of the solution. The carrier oil, BA/BB, any other constituents, and the respective ratio of each.
If the prop was made with 2/20 BA/BB, 50% EO and 50%GSO you could probably use a 27g. 100% EO or some other exotic carrier oil + EO would also let you get away with a 27g.
If it was made with 2/15, something like cottonseed oil it might move slow through a 25g even.
And radar is right, pins are designed to bend, not break. I think you people don't realize what it takes to prove a product is safe, or that failure modes have been sufficiently reported and mitigated to the FDA to allow for product approval.