I'm unsure when to start the time on C64 Pac-Man. The 2 existing 10,000pts runs start on last menu input before game start. I don't mind this but it should at least be clarified in the rules. I would personally go for something like "Time starts when 'READY!' appears/reappears onscreen as the jingle starts" to account for the ingame Soft Reset function.

Certain Commodore 64 Pac-Man ROMs ask to enable things like Invincibility, Infinite Lives, etc. I feel enabling these settings should be explicitly banned in the rules. Use of the ROM itself is okay; as long as they press N to deny enabling of the cheats.

C64 games can run on either PAL BIOS @50hz or on NTSC BIOS @60Hz, meaning NTSC runs games ~17% faster. Games such as Mario Kart 64 solve this issue by converting times, since that game behaves exactly the same either way, just at a differing speed. This may work for C64 Pac-Man but I am unsure if the same ROM behaves the same way on different BIOSes. Another option is to find out what BIOS the game was intended for. If for the slower PAL BIOS, then ban NTSC. If for the faster NTSC BIOS, then PAL becomes obsoleted anyway. A game's sound design can sound too fast or too slow when using a certain BIOS, meaning this can be used to presume a game's intended BIOS.. blah blah. I can't tell one way or the other for C64 Pac-Man based off of sound nor can i find anything online so.. whatever the mods decide, whether it be banning/allowing NTSC, or making separate categories, is cool wit me.

NTSC is allowed.

Also, to keep things consistent, when you press start to begin the game, that is when timing starts for all versions.

The arcade version has you insert your credit, select 1-player, then you press start here to begin the game. Similar to how you describe the C64 runs.