Add to this that most people on this forum are also a little wiser regarding sub placement, and that stacking your DR tops directly on left/right placed subs is far from ideal as you are loosing the benefits of correct sub placement, however its also probably the safest way to stack your tops, so its a safety/sound judgment call....
Most people will not be able to afford the several thousand £/$ for one of these standard 'compact' array stands:-

And if you could, a pair would need a van of there own to transport....
This is the other traditional method of supporting arrays:-

Again cost and size is the big restriction for most small bands.
This thread is to try and compile a list of different ways of stacking your DR's safely, but still in the reach of the typical club/Bar bands budget.
Keep in mind that all the ideas here are simply to try and get a simple and better solution than single tripods that lots of guys are using.
As a picture speaks a thousand words its of great help for any ideas to be backed up with a sketch. 'Google sketchup' is a great way to do this quickly.
Remember the golden rule, any ideas shown here are just that, ideas. If you try something its at your own risk,best make sure your public indemnity is upto date.
Dave Perry