Taking the time to properly research about the different aspects of building a luxury custom home is of paramount importance. You should focus a lot on the style and the design of the home. As the client, your focus should be on these aspects. You should not focus too much on the construction aspects. You should leave those things to the custom home builder.
You should definitely talk to an experienced loan advisor as you would need a lot of money to build a luxury custom home. So, you may have to take a loan unless you are a very rich person. Getting a loan would take at least around 2 weeks of your time. But once you get the loan, you can relax a little.
Many people make the mistake of not hiring an architect to build a custom home. This is a bad mistake actually. A good architect is someone who would make sure that your home is structurally sound. You can talk to your builder and ask for recommendations about an architect before starting the custom home construction project.