Instead of using the Toyota cross bars I am making a set of cross bars out of SuperStrut. Works like a charm and mounts into the rails just like the tie downs (leaving them free for other things). Materials so far is less than $25. I will post pics when I finish them up.
As promised here is what I am doing for crossbars.
8 - 3/8 x 1" bolts
8 - 3/8" cut washers
4 - SuperStrut angles
2 pks 3/8" SuperStrut Spring Nuts
1 - 10' length of 1/2" SuperStrut
For those that are unfamiliar with SuperStrut, it is a product used primarily by electricians for making wire runs and chases. It is quite strong and it all galvanized. I used the 1/2" but it also comes in a thicker version that is is beefier yet.
1. I order for the spring nuts to fit in the 1/2" and in the bard rails of the truck, the springs need to be removed. You can break them off with some effort or just cut them off with sidecutters. The angles have one leg longer than the other. I used the long side to attach to the bed rails to set the bar a little higher. There is front and back to the nuts. The bolts go into the side away from the spring. The angles are also predrilled for 1/2" bolts, thus the washers.
2. Pre-assemble the angle with the bolt, washer and spring nut loosely. Remove the trim clip at the back of the bed rail and slide your angle on with the spring nut sliding into the bed rail.
3. Repeat the process on the other side. Then insert the bolt, washer and spring nut (again loosely) through the top holes of the angles.
4. Next cut a piece of SuperStrut to approximately 57 3/4" length. You could make it a bit longer if you wanted it to extend to the sides more, but you want to make your cuts in the middle of two holes. The next step takes a little wiggling around. Slide one end of the strut onto the angle, with the spring nut inside the strut, then move it past a little ways and bring it back onto the other side. Center it up, tighten it all down and you are done. Note: Do not overtighten it on the parts in the bed rail or your could mash in the rail edges.
Since all the parts are galvanized, rust is not a real issue. However, for looks I am going to prime and paint them black. I have not got the Safari Rack yet so I am not sure how exactly it will mount to these cross bars, but these are going to be much stronger than the OEM cross bars.