i may be able to help with the camera resolution and the quality of the model
It is all about the size of the pixel on the cup, known as Ground Sampling Distance,GSD, by aerial photographers.
Since you have a high resolution camera and are taking your photos from a very close range, im guessing no more than 30cm away, the size of the pixel in real life is going to be very very small, under 0.1mm i would guess. When photoscan makes the dense point cloud the quality you choose dictates the density of the point cloud based on how many pixels will be used.
Ultra High:Every pixel
High:Every 2nd pixel
Medium: Every 4th pixel
low:Every 8th pixel
Lowest: Every 16 pixel
i.e. If my ground sampling distance was 1mm and i choose medium quality, then the dense could would use every 4th pixel in a photo to produce its dense cloud. therefore i would have a point every 4mm
the lower quality images would produce a better result because the GSD is lower so smooths the models out. if the GSD is to high then you end up with a lot of "noise" in your models as there is always a certain amount of error in every point, which becomes very apparent when you have a lot of points very close together.
My suggestion to you is to decide on how far apart you want the points on your cup model, then adjust your photo resolution to be 4x better than what you want. This will give you room to play when you produce your dense point cloud. There are GSD calculators our there.
I hope this makes sense and note that massive resolution cameras are not the be all and end all of photogrametry.