You can probably youtube videos of cleaning injectors. That should give you an idea of how the injectors are spraying. You said kit so, assuming it's a plate, you can check for straightness for a good seal. Problem is, some kits are not machined correctly for the proper gasket/seals and can, and will, still leak.
You could pull the injectors and have them bench flow tested and/or cleaned. I just replaced my 750cc PI injectors after running e85 for apx. 40k miles because two of them were getting stuck open. This was after having them cleaned. Not sure if this is common, but might be due to running straight e85 daily. Like said above though, depends on what you want to test.