This has always bothered me during field mapping: A boudin with two stretching directions has the form of an M&M candy (or almond shape). What do I do to measure the two stretching directions if the surrounding rocks don't show any stretching lineations. Does anybody have experience with this?
If you can't get a macroscopic sense of lineation, try microscopic measurement (thin sections along the supposed plane principal stresses) and transfer them in macro. The Techniques of Modern Structural Geology: Strain Analyses Vol I would be very useful for reference.