Ok just to show some of the science involved with the turbo oil drain, this is the general rule.
Attachment 50627
Now acording to my service book there are two types of sumps for the td42 in a gq, one has a 7ltr capacity and the other is 10.5, this one has the 10.5. That capacity is usually to the windage tray or just above so the big ends of the crank don't get a restriction from the oil itself while its rotating.
This is the full mark on the dipstick which is about 2" from the sump gasket
Attachment 50626
This is where the turbo drain will drain from into the sump
Attachment 50625
And this is where it will sit inside the sump itself, notice how much higher it is over the windage try
Attachment 50624
I'll post up the final result later on