Have taken over a 17,000 that another company had prewired and semi-installed. We were lucky that everything was well labeled. Figure that you may be working on this home for years after the install with potential upgrades. DOCUMENT everything! That is one of the smartest things to remember.
Crestron is great stuff, Lutron(?).... I would certainly prefer Vantage. It is much better.
We are just starting a 26,000 and it has to be prewired by someone else... union.