Lauren,
When I tested for my husband we were 0/6 match. I was disappointed and felt, as you do, that I wouldn't be giving the "ideal" kidney. The center told us that the antirejection drugs and regimen nowadays is so sophisticated, that the antigen match becomes almost immaterial.
I do think there are other things that come into play such as the health of the recipient, reason for kidney failure, underlying diseases/conditions, etc. rather than the antigen match. At that 0/6 match, my husband is on minimal antirejection medication compared to others we know that had better matches.
It sounds as if there are other concerns that you have, but I wanted to at least share my experience on the antigen match. Best of luck to you!