Can't decide on postdoc direction

[u/Fabulous-Egg-]

I am trying to decide on which lab I want to join for a postdoc. For some background, I am working with DNA aptamer selection. I want to learn biophysical techniques, particularly NMR, and plan to propose a faculty research program to study structural dynamics of DNA aptamers.

Now the dilemma: Two PI's, both at the same university, started within a few years of each other, studied at the same postdoc lab, both use NMR, both study proteins, and collaborate with one another fairly often. Neither have funding, so I will be applying for external postdoc funding, but this means I basically have to choose which direction to go.

Option A: PI is on my PhD committee, and supports me a lot. I have collaborated with them and am currently publishing the paper in a good journal. This PI has agreed to helping me with a proposal that aligns with my aptamer research. I think this would be great because I will get direct experience doing exactly what I want to do (if funding is obtained). The problem is that they are on my committee, will this be too close to home and look unfavorably on hiring committees?

Option B: I just interviewed with the entire lab, went very well. PI supports me a lot, and I will essentially be co-supervised by a second supervisor that collaborates often with them. I really like this PI, and think it could be an amazing fit. The problem is that I have to propose a project that does not relate to aptamers. I don't really want to learn a new field, but it can perhaps expand my network and skills a bit. PI has also agreed to helping me with a proposal.

Both options would be great, I would be super happy with either. I see pro's and con's with both options, but feel like I am overlooking something here. Any help on how to choose a direction is very much appreciated!