Fortunately, the speed in the propeller plane is not zero once the propeller runs. It will suck in and accelerate the air ahead of it as much as it pushes air out the back, accelerating it further. This was already formulated by Robert Edmund Froude and is called Froude hypothesis. Read this answer for more.
Using the equations from the linked answer you can already calculate your propeller's efficiency and the flow speed in the propeller plane once you run it on your test bench. Most likely your propeller is designed for more than the flow speed achievable with static conditions, so this will help you to calibrate your calculations only for low prop speeds. But since there is a flow speed already, all equations will work.
Your propeller has an advance ratio that tells you how fast it should be spun for a given flight speed. In order to extract more thrust, the propeller should be spun a bit faster, so a positive angle of attack at the blades results over the whole propeller span.
In static conditions, you will not achieve a good angle of attack over the whole span. The faster you spin the propeller, the more it will experience too high an angle of attack, a condition that will be worst at the root and only the tips will exhibit close to proper flow conditions. Since the inner part of the propeller is stalled, it will create lots of drag for little thrust. Therefore, the max. RPM and torque numbers are very hard to predict, and measurements at that point will be of no value for predicting the behavior of the prop once it runs at its design advance ratio. Air density should be less of a problem - it will drive up dynamic pressure and, consequently, the power which is needed to run the propeller at a given speed.