I am currently using that left blower duct and IMO it works better than the stock QiDi version.
Printable View
I've used this one with dual extrusion prints in PLA.
http://www.thingiverse.com/thing:1542849
Yeah, same as the one that you listed. http://www.thingiverse.com/thing:1716089
The last mod was the addition of the little flanges that fit into the blower's output opening. First version of his duct lacked those, so it was difficult to align and lock in place. It leaked a bit more too.
I am trying to decide between the two right now. I am going to print one of them in a little while I just have not decided which.
The first one looks interesting and like it not only works well but gives you a better view of your prints if you use a corner cam like I do.
The second though where both sit behind the nozzles seems like it would be great as well.
As for removing support material. Use leaky supports and you can use one of those small straw brushes to clean most of them out it looks like.