This is as common as White Honda Civic Hatchbacks.

OK, Most of the screw heads are softer than a stamp collectors hands and the things will just get chewed up like cheap bubble gum.

The best bet to get the screws undone is to get ya self a cheap  impact screwdriver, I bought mine from harbor freight.

Then I basically use the Phillips fitting on the screw head, then bash the balls out of the impact and the screw will come undone.

Once they are out and you want to replace them, I use stainless metric Allen head bolts.

These will last bloody years and come undone so much easier years down the line.