So, my current workflow, is in Revit, I'll route piping using default Revit piping, strictly for routing concept.

As the project advances and more detail is involved, I'll grab my piping, select "Design to Fabrication" and apply my service, and all my Revit piping becomes Mechanical Fabrication Piping. And at this point, I start fine-tuning the piping with "real" stuff.

What I'm trying to find, is where in the "Design to Fabrication" step is my ability to set something for a default?

For instance, right now, I draw this Revit piping as buttweld, then when it advances to the next step, I grab it, convert it to Fabrication, and everywhere I have a Revit tee, it becomes a Weldolet after conversion, and not a buttweld tee.

My Buttweld Tee button is set for "Branch-90" and my Weldolet is set for "StabInSocket". 

I'm looking at the button mapping in the service, but I'm trying to decipher what, exactly, it's doing.

Anyone have any good resource for button mapping?