Denny,
I'm a little late to the party, but after looking at your pictures I have a concern. It doesn't look like there are any bolts going through the joist, so I'm assuming you just lagged the strut to the bottom of the joist. If you attempt to pick a load up from one of the corners you will have the entire load hanging from just one screw which could pull out of the joist.
Here's the way I'd support the system (see link), at least on the corners. I hope you already have something and I just don't see it! Would hate to hear you dropped some heavy item and got hurt.
http://s160.photobucket.com/user/st...5254_zpsm2tivmo0.jpg.html?sort=3&o=0Mike B
