Quote Originally Posted by shazza View Post
...snip... My concerns are 1) how to hook it all together so it's stable, yet can be lifted out of the bottom compartment,...snip...
If it were me, I'd whip up some round rods (8 to be precise) of the proper spacing length that had 6-32 right and left hand threads and thread them into the rads. Seeing you unlikely have the same equipment I have (lathe ), maybe go for some reasonably thick sheet metal (perhaps 18ga) strips bent to the proper distance and screwed into place?,. . .or maybe even use 2 full set of UN's rad brackets to hold the rads together? Heck, if you use 3 sets, you might even be able to provide a method to mount the pumps with a UN pump mount as well.