I have an assortment of philips screws; head is slightly wider than the Honda screws. They are zinc plated and made out of a harder alloy. Why don't you use something like that? It is closer than stock, cheaper, and how many times do you crack your engine open? Chances are that copper grease prior to installation, and a good-fitting screwdriver tip for deinstallation, will make things easier when disassembly time comes.