Designing always as restrictions and goals. When you design for testing you want it to be build FAST, and flexible enough to FULLY EXPLORE what you think is important.
For this Process we use Onshape to design, and Slack to communicate and work out our designs. you may also want to use inkscape and the laser cutter for more rapid protoypng
If you are making CADs for this design take the time to make your part configurable. This will save you hours of time as you change and change your design in the build process