I haven't tried that combo in specific, but I'm thinking of giving it a try.
My favorite topper on my silver car at the moment is Insulator Wax with a couple drops of #7 applied via machine. I imagine DWG would have a very similar, appearance.
It's probably better to do a layer of DWG and then apply 845. Each is probably different chemically and mixing beforehand might screw up the chemistry.
I usually put down a layer of Collinite 476, then use DWG on top. My thinking is that 476 will offer great protection and long wear. After a couple of weeks I'll add DWG for added shine. I don't think DWG lasts long enough to use as the only LSP.
I use 476/885 as our winter wax, several layers lasted well last winter, still beading nicely in April. Topped it with DWG/DPS/DWG for the warm weather months strictly for looks. Will be putting on 476/885 again for winter.