I get the attraction of Concierge service when on a big dive trip. When I was a new diver, this seemed like an attractive option. Until I came back to find the cylinder mounted WAY too low on my (then) BC... smacking me in the butt. They can't know how to set your stuff up to your specs (top of plate at tank break, for me)... So you can't blame them.
Just be polite, tell them you 'got this' and take ownership of your own kit. We've all been on vacations and watched vacation divers struggle with how to set up their rig... regs backwards or upside down, Octo flapping in the breeze breaking off things on the reef, tank way too low so they're diving all swawback, mask leaking because their strap is twisted or their bangs are under the skirt, etc, etc, etc....
Self sufficiency at the dive site it the first display of an experienced diver. Self control in the water is the next.
- K