I have been asked to attach a small solar charger panel for trickle
charger (maybe 6 inch square) thingy to a garage roof which has concrete
type (not slate) roof tiles.
I wont see the job until Saturday so cant be 100% sure about anything.
Whats the best way to attach it, I first thought silicone but I doubt
that would adhere to the tiles, Then I am thinking just slip the bracket
(presumably it has one) under a tile.

Any other thoughts? Could I drill into the tiles and use a small screw?