I would agree around 3 months for comprehensive testing, but...

I would agree around 3 months for comprehensive testing, but results might be delayed if they decide to optimise processes and retest, or try different combinations. Material science isn't my area, but from what they mentioned: ASTM standards - "hardness, strength, porosity and chemistry analysis" .

Hardness (ASTM E-18) - print some material (big or small) and use something like a Rockwell Hardness Tester to see how much force it takes to make an indentation to the material. More force - higher hardness number which is great for gear teeth, less force - lower hardness which is preferable for material that has shock loading like the centre of a gear and therefore higher fatigue strength. Strength - tensile testing with dogbone shaped 200-300mm length where you essentially stretch a round or flat test piece until it breaks to determine elasticity, ultimate strength, failure curve etc. So not big pieces. A scenario may be that they print a big block and cut out a 100 test pieces across the block and test them all. Shear testing with similar sized shapes. This will be to the ASTM standards which specify the size of shapes but as far as I am aware they will be small pieces. Porosity - not sure but essentially print some blocks of material (big or small) and then take cross-sections, put it under a magnifying glass and see if there are any imperfections. Chemistry - not sure what tests.....

I think heat treatment will be included as another variable in these tests as a comparison. So get a bunch of samples together from the same print, then test half without heat treatment, and the other half with varying levels of heat treatment. Lots of data here, so it will be pretty comprehensive.