Roof mount Solar

[Steve079]

When installing a roof mount system on a RV, do you try and secure the mount brackets into studs, or just thru the roof sheeting? The Renogy panels my son in law bought, came with some 2 1/2" wood screws, I'm thinking those are way too long if you arent hitting studs. Somewhere here, I think IO read they use particle board, but its more likely to be OSB or plywood, right?

Thanks for any help!