Aldora, Pepe, Island Divers are all shops I have used from up north. Aldora will not have you back by noon unless you have dove the northern sites, as their dives are typically 70 minutes plus depending on the particular dive profile. I love staying north, but it does make for a longer day since the majority of the diving is done 30-60 minutes by boat south of there. For me that is not a deal breaker and my non diving spouse and the rest of the group know I wont be back until 130-2 depending on the dive sites that day.