Tanks on Flatcars - Tie Downs?

I've not messed with the off the shelf cars because I never seem to get around to it, but I've built some kit models and mounted them on flatcars. The black blocks that come on the MTH flats come off, but there's holes in the deck, so you need to fill them in. If you weather the deck, you dont need to worry about the holes because you wont see them on a weathered deck once filled. Scale 8x8s (3/16" square) basswood seems to work pretty well for bracing. You can also sand it into a wedge for blocking the tracks. The shermans dont hang over the side of the car, but some armor will. You can buy chains, tensioners, eyelets, etc.... from walthers and probably many other places. Doing them with chain is a pain. There's a product out there called EZ-line, it comes in charcoal which looks quite passible for steel cable. Its flexible so you can pull it tight, and sticks to itself with a dot of superglue.
Find/sand down little pieces of wood to fit in the stake pockets on the side of the car, put an eyelet in it, loop the line through and then through the tie down rings on the tank. Cross the lines. Tanks were also tied down by running lines through the idler wheels in the tracks.
Here's a deuce and a half:

Let me see if I can find a pick of the M10 I built... (EDIT: Found it)

I have a similar one.  I have actually screwed the tanks to the flat car in some cases.  Mostly home builds.  I use Corgi tanks.  The top and bottom halves are screwed together.  I just locate the holes on the flat car and buy longer screws of the correct diameter and pitch and screw the tank down to the flat car from the bottom of the flat car.  The screws do not show because the shank is masked by the tank treads/wheels/drive train and the screw head is masked by the ribbing on the flat car sub structure.

Those are cool.  I'll look around for some of those detail parts.  Thanks!