I don't have a spotter yet and my not be able to afford one by the time I go. I was leaning to the 12 but don't know. 25oz didn't seem too bad for binos.
I had some 8x32 binos and they didn't do it for me. I went with the 10x51's as a compromise. I will use them a lot around here hunting new planted pines we have . I think you are right the 12x's are too much.