I had an interesting experience bringing my new (to me) 35' sloop from Florida to New England over 10 years ago. My first mate for the trip was an experienced offshore sailor (transatlantic, Bermuda 1-2, etc.). When he met me in Florida, he went over the boat with a fine tooth comb and assured himself of its condition and that we had adequate offshore safety gear (we carried storm sails, but I borrowed his life raft). He went aloft to verify the storm rigging, waterproofed the fuel tank vent, checked out the SSB, etc, etc. We had a loran and GPS on board that had been serviced by Raytheon before we took delivery but he brought his own 2 meter ham radio, GPS, and sextant for backup. All of this was reassuring, of course, for my first offshore experience.
Conditions were favorable and we actually made 2 offshore passages of 600 miles and 225 miles. I was nervous about my first offshore passage, but it was my decision to ditch "the ditch" after conferring with my crew.
My first mate made it clear that I was in charge. He was very laid back about the whole trip, and made it clear that he expected me to act as skipper, which included all decisions about itinerary. Fortunately we started our journey with the understanding that there would be no time pressures and that we could go offshore to shorten the trip, or not.
We didn't have any major crises, but did have some anxious moments, which we survived (obviously). I don't recall any occasion where my first mate suggested a course of action, but he did tell me--after the fact-- that he appreciated my decision to seek a harbor of refuge in the Chesapeake as the winds approached 40 kts.
In retrospect, I was very fortunate to have this individual aboard for the 2 1/2 weeks to took to reach our home port. It was a learning experience for me and the lesson was that it was my boat and I was the skipper. He was quite willing to offer advice when asked, but made it clear I was in charge, despite the substantial difference in our expertise. This was more about the responsibility to make appropriate decisions, rather than than expertise--as it should have been.
The bottom line: it's your boat and you are responsible for its operation. If you have expert crew aboard, that's great: they can provide advice, but the decision to act on that advice is yours.