I agonized over photographers in the very beginning of planning. I wasn't happy with either approved photographer. Be careful if you use Caribe. I forget which packages but the lower priced ones don't include retouched photos...so basically unless you spend over a certain amount all shots are point and click.
I found Matias cano to be pricey with mediocre pictures.
For amount of hours...Do you want getting ready pictures?
I would leave an hour just for that.
Max 30 minutes for ceremony.
Cocktail hour and Pictures
Depending on your timeline for reception you may not need 6 hours. You can do your dances during the salad/soup course & cut the cake early (doesn't have to be done at the very end)