My preference when traveling together with someone is also to have seats F/K with the same numerical number. This is what I would recommend for the OP.

However I do like the A seats when traveling by myself as there are less foot traffic since those seated in F will enter/exit in the same isle as those in K.

Whatever you do, be sure to avoid 1A, 1F, 1K as those are the cloest to the lavs/galley area thus the most commotion noise.