I doubt anyone can tell if the offset is off by 1ms so you don't need to worry about that; we don't even consider hit objects unsnapped if they're off by less than 2ms
in practice, if you can get within 10ms of the correct offset, it'll be fine for the vast majority of players anyway, so personally I don't stress about it too much
if you can't, don't worry, you'll get better with practice. it can also be helpful to use a skin with really clear hitsounds while timing; placing some circles and listening to them tends to help me more than the metronome in the timing tab
plus if your target audience is skilled enough to actually recognise single-digit offset errors, you can just ask one of them to check your offset if your hands and ears aren't precise enough