IMO doesn't really matter how hard you tamp as long as it's consistent. But yeah makes sense to keep it simple for this, plus muscle memory is surprisingly accurate. Post up some pics when you're done!
I guess a tamper like that is only useful in a cafe-type situation. Where loads of different (not necessarily very experienced) people are making coffee throughout the week, whereas the customers expect the same coffee every day.
I considered adding that, but it would add a lot of complexity and would probably require re-adjustment every time I switch beans.