Hi Lauren,
There are often other sensations, some of which can be described (puffiness or bogginess, and rarely, sensitivity), and some that can't (your hand just feels drawn to the area, or it just feels right to cup that particular region or point in your hand). Lately I've been using infra-red imaging to help me literally see the active points. I'm going to lecture on that at the AHVMA conference in Louisville this fall.
Regarding sourcing Seirin needles, you can probably buy them from ITM. Dr. Mona Boudreaux also stocks them, I believe.
Have a nice Christmas,
Steve