Caribou,
A few things come to mind while trying to answer your questions. So lets put forth a few things for you to consider:
Where are you staying at PDC? That may have a bearing on your plans. A trip to Coz from PDC is just about gonna burn a real full day...be kinda sure things are locked in before you go. Your diving level is a consideration. Are you very comfortable in the water and is your buoyancy control very good...Now, you'll be looking at acouple of different things in both places. Almost all of the diving you'll do at PDC involves entering a boat FROM the beach with all your gear. Wind and surf conditions can make this a little sporty at times, particularly when SE breezes are brisk. Almost all diving at Coz involves getting into a boat from a dock. I'm assuming you did you OW in California.....if I'm correct you are used to surf, surge and heavy gear, etc. Also, after diving PDC you may just decide to do all your diving there and save Coz for another day. After all, you could do 4-5 dives at PDC in the time you'll burn just to say you went to Coz. Tortugas is a great dive and I've seen as much on that reef on some dives as anywhere, big and little. Coz has walls, heavier current (makes it a little harder to smell the roses) PDC is not as deep, current less heavy and plenty of interesting fish and things to see. I like to dive with
www.sealifedivers.com. Luis runs a good op and they are located on the beach at Mamitas Beach (Topless) and there is a small restaurant next door that gives a discount to his divers. Parties are very small on the boats they use. We would op for one of the small hotels nearby rather than an all-inclusive. We've done both. At any rate, you are going to have a good time at Playa! PS, regardless of what you do.......tell the people right out front what your dive experience/level is and what your comfort zone happens to be.....they will respect you for it and they will work harder to enhance your dive experience.
Regards,