When an installer designs a custom multiroom music system for a client, he starts with choosing a vendor's base system that he is familiar with and adds elements from that same vendor or complements it with third party equipment to fulfill the specification.
Each project has its own particularities, because of the size and layout of the rooms, the quality levels expected, the difficulty to embed high-tech gear into building structures, the budget allocation, etc.  Most installers who have travelled the road of custom system design know that to to deliver a flawless system which goes beyond customer expectation, a far greater effort is required from their imagination  than the product vendors would like you to believe when you browse their commercial and technical litterature.  And they also know that at some point, there is no going back on a flawed design.  That's why we thought it would be interesting to list the basic do's and don'ts and to bring good value advice in the format of a two-sheet whitepaper by stepping into the shoes of the installer.