I just bought a 2hp DC and a trash can separator. Works great, but I am
short on space and I didn't realize how much room they take up. Especially
if I try to avoid sharp bends between the DC the TCS and the tool.

So, I had an idea. I can build a table on the DC dolly and put the TCS
above the DC blower/motor; it would cut the floor space requirement
dramatically. Since it means routing the air 180degrees from the bottom to
the top, I can put a 5" elbow off the DC, a piece of 5" pipe up a couple
feet, a 5" 45 elbow, a 5-4 reducer and 4" flexible to the TCS. I figure the
5" elbow and the gradual bend on the top will minimize the pressure loss.

Does this seem reasonable, or am I overlooking a problem. Yeh, emptying the
TCS will be more difficult, but that seems a small price to pay if it is the
only problem.

Second question... I would have to buy the 5-4" reducer and the 5" 45
elbow. The DC came with a 5-4" reducing Y. That could replace the two
parts I would have to buy if I simply seal off the other 4" opening. But,
having done white water kayaking, I can see it introducing eddy currents and
other turbulance that might make my $10 saving foolish. Whatcha think?