So, how much can I mess up if I get the tool to open the watch properly. We have two places locally (that isn't the small hole in the wall kind of place) and one of them only referred me to the other place that had me pay 34$ for a battery replacement on my Seamaster, that's not including pressure testing it (that would have been a 51$ total). Maybe I'm wrong but these prices seem quite unreasonable? So, how bad could I potentially mess it up if I did it myself?