The Pro 48 is Amigos big dive boat for the long haul trips. There's a nice picture on their website.
As for your ear problems, if you have trouble equalizing on the Blue Hole dive, you only have a certain amount of time, 3 minutes or so, and if you are unable to equalize and meet up with the group before the descent over the ledge, you must return to the surface. No Blue Hole dive for you. Therefore, I recommend you do not bother to go on a Blue Hole dive day trip until you have your ears sorted out.