From what I've been reading / watching on YT, it isn't common for divers to do a two tank shore dive at any one location in Bonaire. My guess is that part of the reason is securing the second tank at your vehicle while you're in the water. And I suppose the other reason is that there are so many other shore locations that you wouldn't want to spend too much time at any single one. How far do you have to drive to get a refill in most cases?