Once I identify the right resin, the next step is to find the right exposure time (or light intensity) for a specific 3D printer.

To do that, there is a simple way: to create a working curve (a good reference: https://www.instructables.com/How-to-Take-a-Working-Curve-Measurement-and-Create/). 

To reduce the amount of the resin, I also made a "well" and put it into the resin tray to confine the resin area.