When you are looking for a new custom home builder, you might come across highly professional individuals or firms. But, it may not necessarily mean that the builder would be suitable for your project.
When you look for the builder who is best suited, you need to look at all the previous projects of the builder as that approach would put you in the best place to judge whether the builder is suitable for your project. You can ask the builder to arrange site visits of past projects or any project he is currently working on. If the physical visits are not possible for any reason, there should be sort of virtual tour at least in terms of videos or photographs or slide shows.
You are going to trust a large amount of money with your custom home builder. Also, you are going to spend a lot of time with the builder discussing on a regular basis. So, you need to make sure that you are quite comfortable with the builder.