It is easy to do that way. After all, until two years ago, we all did it that way. It also depends on how complex your setup is. If you just have two controllers with 1 output each, it has to be quite easy.
But now, if using xLights, you can basically do an expert configuration job from within xLights. The visualizer is huge help to laying out the props and getting the config correct. The exact start and end channels without worrying about about, oh I moved that, what are the channels now? In addition to the config outputs, you can also uploads models to FPP. This gives you model level testing from within FPP and the ability to do some things that would take more work do other ways like button input to overlay a prop.
In your case using teensy, I don't think there is a good fit for controller and model that let you do all that stuff so you are probably okay doing it your way.
What software are you running on your teensy? How many ports do you use?
