I reproduced this tenor recorder from Adrian Brown's Museo Nazionale PDF. This instrument is known as "Rome 716"

In order to print, I suggest having each section mostly vertical - you can print up to 10deg off vertical without negatively affecting the barrel. Do note, this is a resin print in order to properly print the labium (the air blade at the whistle part).

To finish this instrument, you need either dental floss or waxed thread to wrap the joint. You also need beeswax.

Wrap the joint with the thread. I include indentations for the joint to properly fit the thread. If its a bit loose, use beewax to gently rub on the thread. This will provide the best air-tight fit. Don't double-wrap the thread, as it can crack the barrel on insertion. (If you do break/crack the barrel, you can use superglue to fix.)

For safety, you can also use a medical grade epoxy thinly covering the mouthpiece. https://atomadhesives.com/aa-bond-fda15-food-drug-administration-medical-grade-epoxy-adhesive/ is a good choice. It's expensive though. 

The picture shows a comparison between a modern Yamaha tenor recorder, and this Rome 716 Tenor recorder. Yamaha is ivory/dark brown, and Rome 716 is sky blue.