unrealistic juggling of prop parameters will get me above 17oz thrust, (i.e. 24oz@prop power factor 5) because the prop is stalled when operated in free air due to it's very wide tips, and other non-conformancies near the prop hub. Stall sets in at abobe pitch/dia ratio of 1.2. In such small props, the tip vortex covers a major part of the prop disk, so I think there is no calculator around that will predict anywhere near correct at these extremes.
Removing the tip vortex as in ducted fan use, like Dar said, may yield higher values. However, this is not possible in my calculator which is for props, not ducted fans.

edit,
BTW Francis, If I set my calculator at prop factor 3.5, I get your thrust, at ~155W motor shaft power (~200W motor input power)
Have you measured motor voltage and Amps?
Just curious and willing to absorb.