I have installed a variety of tilt frames on tile roofs but as solar has become much cheaper it's not really the best idea. If you're dead set on doing it, see that the framing systems uses something like unistrut to tie all the mounting points together into a unified chassis, then build the pitched solar framing up from there.
This tile roof has a subframe to enable it to be built at an angle to the gutter. The overarching requirement here was to get away from trees shading what would be the better side of the house.
This as yet unfinished subframe is being built to carry reverse pitch solar panels. Customer insisted it must not be seen from the street.
Subframe of 50mm square hollow section aluminium tubes.
Be Wary Of Tilt Frames On Tiles
Seeing as angle frames create long shadows, you'll usually get only one row on a south facing roof, where three will fit if they're laid flush. South facing solar is actually not a bad idea, as mentioned in this article.
Standard installs use fixings with a little movement.
Conventional tile roof hooks are designed to have a tile lapped over the top so they're mechanically waterproof but this means they inevitably have some flex in them. It doesn't really matter when the array is parallel to the roof, but having tilt frames mean there's a big sail to catch the wind and a lot of potential for rattling and even broken tiles.
This tile split lengthwise when it was stepped on but it shows how a typical tile hook lays. If there's trouble, typically it's the tile under the bracket under that cracks, and leaks.
Using hangar bolts is a much sturdier way of doing it, but they must be screwed into the rafters, which means you'll seldom get through the ideal part of a tile, rather you'll have dozens of holes relying on silicone sealant, not gravity, to prevent leaks.
Hangar bolts are the only option on some roofs such as slate or really flat shingles.
Some installers can think outside the box, which is another way to maximise the roof.
These examples on a metal roof are probably easier than tile, but offer solutions all the same.