Is there a superior suture material and technique for better upper blepharoplasty results?

Sutures dont make a long term difference in terms of scarring. Absorbable sutures tend to come out/break a little easier so you have to more careful with touching and rubbing your eye. They are often more comfortable when lubricated so most common lo y are used on the lower eyelids so the eye isn't as irritated. However, surgeon preference is the most common deciding factor. This shouldn't be the issue you are too worried about.

The most important factor in achieving the optimal scar after blepharoplasty (or any other procedure) is the skill of the surgeon and his or her attention to detail.  The particular suture used or the closure technique utilized is of limited importance.  However, timing for suture removal may affect the outcome; sutures left in place too long could leave marks.  Some dissolvable sutures may not "fall out" early enough and could leave the track marks I am referring to.

On patient with thin skin, typically Northern European background, a buried running suture can work well. For other ethnicities with somewhat thicker skin, I prefer a combination of interrupted and running sutures. Interrupted sutures give a more precise closure but are tedious (and tender) to remove, so a running is combined to reduce the need for interrupteds that run full length.