The screw idea was based on 1) attaching a vehicle to a base that would be moved around alot (like going to shows) and the vehicle would not move off the base. Even if bumped hard. 2) to give the impression of weight to the vehicle so it would hug the ground and not float on dirt clogs or tufts of grass as 30-60 ton vehicles are not supposed to do.3) you could remove the vehicle to change out the base, use the vehicle on a differnt base or diorama or make changes, repairs mods and not have to risk pulling wheels or tracks off or large sections of ground work.
If you set your vehicles into your groundwork before it sets up and is still soft, you can make the impressions needed to firmly anchor tracks, tires, skids etc. and make it look like its got weight. The resultant impression made by the tracks or tires are more then enough to give a good holding surface and a "well" for white glue to keep the vehicle attached. Let it squeeze up through the tracks and it will permanantly attach the vehicle to the base. If you don't want it to be permanent, you can soak the attachment points with water that will soften the white glue and you should be able to remove the vehicle with little or no effect to either base or vehicle. The impressions are custom fitted to your vehicle so it will fit snug as a glove.
Mike
"Imagination is the dye that colors our lives"
Marcus Aurellius
A good friend will come and bail you out of jail...but, a true friend will be sitting next to you saying, "Damn...that was fun!"