you’d need to check the trichomes to be certain. I’m guessing you don’t have a microscope or loupe to check? I don’t either and use an app nineX to check. Doesn’t work perfectly but gives me a better guesstimate on when my buds are ready.
Most strains flower completely in 8-9 weeks, however some strains can’t take longer and up to 11-12 weeks. They look ready to me though.
To your second question, the buds look a good size to me.
there’s many reasons for size of buds, including both pot size as well as lighting but so many other factors such as seed genetics, environmental control, nutrients and application thereof, stress, pests, temperatures, watering balance, airflow, etc. Literally every input can affect your bud sizes.
Your plants look really nice though, so definitely a job well done.