All right, here it is. I adjusted the dimensions slightly to center the spout of the intake a fraction of an inch farther forward in the chamber, closer to the actual L/8 point. This takes the tailpipe end correction into account better, and should help with the slightly reduced overall length of this version.
Note that the 'pinched dimension', i.e. the width of the intake shell, is not shown. It will be discovered as you pinch the pipe gradually to get the internal clearance [0.42 inch or 11mm] shown. Once you have that, the shell can be easily used to mark the front end of the tailpipe for cutting out the notch for the 'tongue'. This width will depend somewhat on the exact tubing size you use - even the tubing thickness will affect it.
This was worked out quickly - please feel free to point out any errors or question any dimension [including metric conversion] that doesn't seem to make sense.
EDIT: I get this to come out perfectly full size if I print or copy it at 97%.