Like most of Robert's more modern designs, the 370c represents a mediocre design (meaning not the best and certainly not the worst) from the 1970's, which is to say that its hull form and rig are heavily influenced by the IOR racing rule that was popular during this era. This was not one of the better design periods in the history of yacht design and frankly we have learned an enormous amount about motion comfort, seaworthiness, ease of handling, and performance and none of those lessons have been considered in this design.
Building a boat is a massive undertaking and I cannot emphasize the importance of sellecting the best possible design that you possibly can. Having been around a number of boat building projects, you will spend years of your life, and for most people, spend more money than you would spend if you went out and bought a couple year old equal quality production boat. When you are done, the effort is only worth it if you end up with the best possible boat that you can. Otherwise, why bother to build.
When I look at the 370, there are a number of freakish versions that make no sense if sailing ability is important to you. All of the versions are absurdly heavy which is anything but a good thing, especially if you are building this yourself because that means that every bit of the boat gets heavier and more expensive, with no real gain in strength, seaworthiness, motion comfort, ease of handling or performance.
With all due respect, I would suggest that contrast the Roberts 370 with the work of Dudley Dix, or Yves Tanton, both of whom have produced better designs. My other suggestion is to look for a 10 or 15 year old boat that started life as an above average quality design and build quality and that is in healthy condition and customize it to suit your needs. You will end up saving a lot of time and money in the long run.