Where did you get your 50mm hose for the CT26?
Remember that I design enclosures and vacuum systems for people.
One of the principals is use the largest tubing/piping one can for a long as one can; even so keep the run as short as possible. Another is to avoid bends and when a bend is necessary make it as gentle as possible; also avoid transitions and, when necessary, make them as smooth as possible.
So I went searching the Festool sites to learn of the available tubing options and discovered the largest diameter, shortest tubing they offered:
Pricy, but serious air flow is possible.
The front door is pretty easy to open when running, even with the Festool turned all the way up.
That’s not a good sign… 
I can tell it has some vacuum, but it doesn’t take much effort at all to open it.
Dust collection is about vacuum AND air velocity. We need air speed to get things going and going well. The standard tubing is good but may not be enough (I’ve never tried it). If you look at my enclosure, I have a 2.5" fitting that also happens to fit the 50 mm Festool tubing. Only there does the size drop.
Avoiding bends is also important. When necessary we want then as gentle as possible.
My downfall may be using the hose that came with the Festool (I figured after paying $600 on a vacuum cleaner after forking out $$ for the Nomad that I would try to spend as little as possible until I start making some things with it).
There are definitely issues with smaller tubing and good dust collection. If you did go for a custom enclosure, we can discuss a modification to use larger tubing. Without the constraint of the Nomad enclosure, more options become available.
I mostly got the Festool to mill PCB after hearing horror stories about the junk that gets thrown around during the process.
Garolite and FR4 produce some of the nasty stuff that affects for your lungs. It’s really important to handle it properly.
You’re mostly there! A few tweaks…
mark
P.S.
If you run the tubing out the front and make it as straight as you can, does this affects things? If so, how much?
P.P.S.
You can find pictures of the fittings I use and how I run things through my enclosure here: