J. Phil Thien's Projects

Pop off the HF DC plastic adapter on the inlet and you have a 5" inlet diameter = worthwhile improvement and really help match better to the Super DD. 5" pipe or hose is available on web for reasonable.

If you are bold, get an HVAC 6" starter pipe (there are some with metal tabs around the circumference and some foam adhesive no-brainer install ones at your big box stores) for less than $10 and a piece of 1/4" hardboard or sheet metal. Make your own replacement for the removable round disc off the front of the blower. There are some pics out there on the web of ones guys have made for the HF. That will be a 6" diameter inlet = BIG improvement if you are running 6" up to the tool itself. If you run DC to the tablesaw cabinet and an overhead guard that will also really help since you are trying to use both lines at once to capture fine dust.

The HF DC doesn't have a lot of power so if you keep the pipe size larger to the one machine you are using it will make a nice difference.
From your description, if those are the only tools you run off of it, one at a time, with 8ft or less of flex hose, then the 5" inlet will probably be fine and do better than the 4". Later, If you run duct for any length, or the TS setup I mentioned, or other high dust producing tools, I would suggest the 6" mod. It doesn't take a lot of time or money. There a other factors to this discussion that could be helpful to decide.

I think the other consideration for a barrel/drum is they are often easier to remove and dump the waste outside the shop rather than transferring the dust/chips from a large box into a different container to be dumped. This causes a mess and generates airborne dust inside the very shop you are trying to rid of such dust.
Some have ducted the waste to a larger outside box (in a shed or closet) that can be shoveled out into a wheelbarrow, etc.

In case anyone continues to read this thread in the future, acrylic will work for this application yet it has it's disadvantages since it is typically brittle. Cracking occurs when drilling (sharp twist angle drill bits help), can crack if you hit the window (poor impact resistance), and does not flex as easily in the thicker sheets.
A better material is polycarbonate or Lexan as a typical trade name. It is far more flexible than acrylic, you can use a thinner sheet since it has far higher impact resistance, and the window is actually more visually clear than arylic.
It is more expensive than acrylic but you can buy half the thickness as acrylic (less expensive) and it will still be stronger, last longer, and be easier to fab.

Most of the home improvemnts stores will have some under Lexan tradename, McMaster Carr, or you can try Tapplastics.com if there is a store near you or you order it online from them. Depending on how large your window is, you probably don't need more than 1/8" thick and and 1/16" may be great for most windows. There shouldn't be any need to heat form this material to the barrel. Carbide tools work best to cut it and edges can be really nice after routing but watch out for sharpness.