Prop for Suzuki DT140 on a 20' MA?

[CaptCurt]

I know there are several old threads related to this... but most ended up going off on a tangent (imagine that!).

I just bought a DT140 Suzuki for my 20' MA. For those guys with a similar rig, what prop do you use? A local shop told me 13 1/8 x 19, and that is what the "prop calclator" on a website said as well. However, it looks like several guys on here are running 14" props pitched at 20.

Experiences? Recommendations?