Here is a
link to my advise on mounting panels.
I probably should add something about the overall layout to the document
* Don't put panels where the AC or other things shade them easily. Even a small amount of shade greatly reduces output.
* Be sure to leave room to walk for inspection, cleaning, and maintenance.
* Route your cables such that they are centrally located and do not create a lot of obstructions for dirt and debris.
* Put UV stable loom over your cables.
* Make sure you can reasonable remove the panels.
* Do not remove the manufactures connectors.
* Tilting is rarely useful. Your will probably be better served with a few extra panels than tilting. Although as I write this I am tilted.
* Be prepared for cleaning and waxing your roof to take 2 to 5 times as long as before you mounted all those panels.