I used a very similar driver on my ultra basic build.I kept it simple so that if I did let the magic smoke out of the box it wouldn't be a financial disaster.Which made me happy to have selected a BOB with opto-isolation.Several of the parts may well find their way to a bigger and better machine one day ,so I totally understand your approach.My next challenge is to understand more about homing and limit switches and then make them work.Other than finding some of the Chinglish instructions a bit puzzling it wasn't too difficult.Whatever components you choose,don't lose sight of the fact that its just 1's and 0's being sent along conductors.