Hi Jbert,
This is what I been using for at least 4 years. I have just replaced the trucks. but keep using the same rack on every one. so this is really strong.!!. (most of my dives are on remote shores, and 4x4 are a must due to hi slopes, loose ground, steep tracks, etc.) and tanks are kept secured and tight.
To avoid drilling or making permanent modifications, I do remove the hook tie down anchors from fornt sides of the bed, and bolt this rack using the same threads. This rack is made from galvanized steel, you can find the rails, nuts, bolts, squares, angles, etc, in the electrical installations area of any hardware store. The scuba tanks are hold in vertical position againts the rack using a strap, with this I can accomodate up to 21 tanks, and you can be sure that they are not going to move. the rest of the gear goes in large and robust plastic boxes.
The rack proved to be multifuntional (see the bike holders) you can hold any think to it. and also helps to prevent damages or bending the wall of the bed. I have seen many beds contacting the passengers cabin.
Hope this idea helps for a better solution
