Should I tape joints during or after an initial fill with setting-type compound?
Tape goes in early. The tape is providing a paper face across the joint just as the paper face of the board does across the wallboard surface, and wants to be bonded as close to that surface as possible.  So, it's generally embedded in the first coat of mud. Mud, tape, mud over tape, build up to a smooth surface.
You are not spackling, you are mudding joints (applying joint compound, which is somewhat universally called mud.) Spackle is a different product for a different purpose.