If You plan on (some day) reaching out past 500 and using scope turrets to do it: get the 20moa base to start with, it will not hurt a thing and you'll have it if the day comes you need it. Chances are with a 65moa scope you could go 1000 yards even without a canted base.......... Depending on caliber, load and conditions.
If you have no intension of going long range: there is no need for a canted base and the 0moa would be the choice.