The bin i removed for the modelling session is the one in the left side rear door; the first picture shows it with one bolt on the bottom portion of the bin. I will have to make a repair to that, as i put, until recently, heavy items in there such as shackles, wheel nuts, etc., that must have banged forward every time i slammed that rear door. I slammed it in attempts, repeated many times, to seal the door properly, since even with the new weatherseal on the door (perhaps because of it, considering the flexibility of the frame around the window), the door doesn't seal properly, letting some dust in. The effect of that slamming bent the bottom of the inside of the door itself, and that bottom nutsert/rivnut has now pulled out of the body. All this to say, if you're going to make yourself a set of these, install two nutserts in the bottom portion of the narrow rear door - it is the door that will likely be opened and closed most frequently after the driver's door. The second picture in this post shows the bottom of the bin and its effect on the body; i believe this is easily preventable. Perhaps an additional strip of steel inside the bottom of the rear door to catch the rivnuts would be of use too, spreading the impact of slamming on a much larger surface.
The depth of the storage area is about three inches, from the back of the large panel to the exterior back of the bin itself; let me know if you want measurements, the three inches is rough. In the last picture here, i tried to show the groove cut into the back of the main plate, there in order to allow movement of the door handle's rod. I do not know the depth of the bins below the side windows.
The bins installed below the side windows are a single unit, and the main plate goes far enough forward that the seat belt goes through it; i recommend that, if it can avoided, do not have that main plate go so far forward: i find seat belts important, and i did have new ones installed when i got the car. However, to have to remove the entire four-bin piece is awkward, on top of which i would have to remove the cargo barrier for that too, which presents another difficulty: the cargo barrier's frame has bolts that go through the floor, and the nuts for those bolts were not welded into place, such that the nuts for those bolts could fall, and putting them back on could be a serious headache, as they are above the forward fuel reservoir. I'd suggest a separate piece of aluminium plate for that area, just so that one can remove the side bins without having to touch anything else. If, for example, you want to add some wiring going to the rear of the car and go through the bottom of the body instead of on top (above the windows), the prep work involved would be reduced significantly. Of course, if you don't have a cargo barrier, that part becomes a non-issue.
If this is getting difficult to follow, pm me, i'm glad to call and yap.