Spirall08,
We seem to be in similar situations. I just had my second HT five weeks ago after my first one 7 years ago which was for my hairline. I had a little more hair then you have now (before the 2nd HT) and transplanted around the front and crown area. Although there was some shock loss it was not so bad and I feel I would have been at this point in another year or two anyway if I did nothing. I never heard a that a 2nd procedure would have less yield, I hope not at this point.