Is this just for testing and it's small amounts? Backlighting and a translucent belts? These conveyors are like $2-5 in parts: https://github.com/GemHunt/conveyors/blob/master/bill-of-materials/bill-of-materials.md
Multi point top and backlighting can be a huge help 3d shape labeling as well.
I wish I had the time to work on seeds.