Hmm... does your SR have the original screws/strap buttons? I seem to recall the screws for the super locks being the same size and thread pitch as the stock screws. They are slightly shorter because they sit at the bottom of the strap button, but still penetrate just as much into the wood. I've got some Schaller locks on a 11lb Heritage H150, and they have the thinnest screws all all the locking strap ends. I've never had a problem at all, nor have i heard about them shearing off. The weight of the entire bass is not nearly enough to break the screws/etc.
only thing to always be aware of is making sure the locks are in fact locked in. Ball bearing locks like the EB super locks and Dunlop Strap locks need to be inserted all the way and kept lubricated to make sure the ball bearings are in the locking groove.