How long after exposure does it typically take most people to show hpv genital warts? im vaccinated with gardasil 4. how common are the strains not covered that cause warts?

Gardasil 4 covers the 2 HPV types (HPV6 and 11) that cause 90% of genital warts, so if you were not infected prior to vaccination, you are very unlikely to get warts. If sexually active and thus could be infected with HPV, there is only a very tiny chance you would get warts; you really needn't be worried about it. But you could reduce the risk still further by having a Gardasil 9 booster.

It varies with the invasiveness of the virus and the persons immune system. Other strains which do not cause warts are as common as the ones causing warts. You did the right thing by getting vaccinated. Getting a booster and still being careful is good.