This is how I built my dust collector and extractor combo. The Dewalt extract had the casters replaced with long bolts sealed with rubber washers. The clear tray is a polycarbonate food storage box I found at a local restaurant supply house. Then the Dust Deputy, of course.
The junction between the clear box and the plywood lid is lined with a strip of 1" wide weather stripping and then held tight to that with the clamps. Honestly the DC pulls the box up tight to the weather stripping with suction so I'm not even sure the clamps are needed.
I had this up in the air on a kayak hoist but I didn't have it balanced very well so for now it sits on the top of a pallet rack type shelf and I have a boom arm that allows me to move it around to my miter saw or follow the patch of my track saw.
The Dewalt extractor turns on automatically with the tool but before I got it I had a similar setup with a shop vac. I had a power strip screwed to the bottom of the plywood carriage and before I started a cut I would just reach up and flick the switch on the power strip and it would turn on both the tool and the vac.
I'm not convinced I'm getting better collection at my track saw but dumping sawdust is so much easier now. I just slide the tray out and dump it in a trash can outside. Evidently these food trays also come in semi translucent polypropylene. I think if I were doing it again I would have used one of those.
Having the DC hose coming down from overhead is really nice. Especially with the track saw.
I just wrote all this and then it dawned on my you had the bucket setup with extractor lid. So obviously the low profile food tray would offer you no advantage. But you could build a side by side setup and put it up on a shelf or something.