One of the things that many people forget about custom printed circuit boards is that products are generally not shaped around the needs of the PCB, the board and all the components generally has to be shaped and specified to fit into a specifically designed case. Whilst there may be some wriggle room on the sizing of the end product, there will be limitations that the PCB design has to fit within. This may well also be reflected in where larger components are going to be placed on the board. If they are right next to a screw hole then there may be stress issues on the board.
Although there is now software and even online interactive websites available to design your own printed circuit boards, complete with component layout, these are not always as easy to use as you may be led to believe. It takes quite a lot of experience to design a good board. One of the better ways is to use a company like ours which offers PCB design services. They will be able to take your schematics and either completely re-layout boards or re-engineer from existing designs. They will also be able to give advice on component layouts and issues such as possible stresses and weaknesses. Finally, they should be able to give you advice on environmental compliance (RoHS Compliance).