The best hold relax position is the patient on the plint with the PT in a power stance with the patients leg resting on the PTs shoulder. Get the patient to push down for 10s and then stretch, passive stretching would be hip to 90 degrees maybe and then trying to straighten the leg.
I find personally that alot of tight hamstrings are due to weak glut medius also, it would be interesting to find a correlation between the two, obviosuly the outcome measures would be difficult in finding the exact strength a patient has for glut med. maybe biofeedback?
Apologies if you already know them hamstring positions which i suspect you probably do, these are the easiest for me anyways.
Good luck,
David.