For clients with headache issues or who are prone to headaches, I always begin and end the work at their feet.
Drawing the increased circulation away from the problem area has worked like a charm thus far.
It sounds like the QRT (Quick Release Technique) published in "Relief from Head, Neck and Shoulder Pain" by Don McCann might be a big help to you and your client. I got my copy of the book from amazon.com, but here it is on his website
http://www.structuralenergetictherapy.com/Books_Tapes.htm. Finding this has been a treasure! It prepares the client for deeper work in a very relaxing way and I've found that at times, it resolves the issue altogether. The principal is the same as that employed by an occipital release. You do some waiting but their body weight does all the work. It took my fingers a little time to get used to it. I've never tried to explain this in type so if something is unclear, give me a holler.
Client supine, MT at the client's head kneeling or sitting in a chair. This can take a little time so be kind to yourself and be comfortable. Slide your hands under your client, when you find the trigger point, curl/hook your fingers (use all four fingers) to hit the trigger point and surrounding area. At each point, just hang out until you feel your fingers sink in and get the release. This appears to work best in the specific sequence suggested in the book. And here that is:
#1 SI-10
#2 SI-14
#3 UB-38
#4 SI-16
#5 UB-10,GB-20,TH-16
That's all there is to it. I use this
often for just about anything in the upper back, neck, head area. It's easy on the client and on me.