For this reason alone I chose pop rivets instead of screws. Looking at the screws and the thin aluminum wall of the cross bar I was not at all confident that they would hold as well as the rivet. Rivets leave a lot more "meat" on the other side of the hole compared to screws and seem to me as a result they have a better hold than screws can offer. It looked to me like I was going to get three maybe four threads at best.
In case you haven't riveted much, relax, it's easy, especially with this:
http://www.harborfreight.com/heavy-duty ... 66422.htmlThis is THE riveter. I've used it a lot and can personally attest to its ease of use, power, convenience, and the confidence of knowing the rivets aren't going anywhere. It's also the one Jeremy at Surf City recommends and for good reason. I've posted this link many times and several folks have gotten one and really appreciate it.
Good luck!