I do mostly exactly the same work. I always take my watch off before reaching into a rack or PC case. I started doing this after knocking it a few times. The body of my watch is perfect almost two years later (Series 0), save for some very light discolouration on one side. I think Apple have improved the glass. I scratched the face of my first watch about 2 months in, and Apple replaced it under warranty (the whole device actually, hence the slightly less than 2 years). I reckon they had some defective glass in the original run. Since then, it's perfect. I wear my watch all day, every day.
Every stainless (silver) watch I've seen has been covered in little scratches (like the back of my iPhone 7+ Jet Black). The Apple Store staff say they "buff out" but I've never tried or seen that. But I believe the Alu body is way stronger than the SS. My next watch will probably be a gold Alu (not available when I bought) if they offer it with a decent coloured band (where is the plain brown, Apple?!).
Not bad for almost 2 years old, worn daily!
P.S. I should have added - I think screen protectors are not needed on the watch, and look tacky!