I was hoping for more contributions on this query.
looking for a lightweight aero frame and also may need a spare set of wheels for rim brake so it goes up and downhill quickly
Really I don't care about tyre width. I'm quite happy with 25c @ 100psi for my 75kg body. Dropped down to 23mm for TTS, but happy with 25's.

After looking on this forum to no avail over the last year, I bought a custom Sarto rim-brake as my new top-end rather than going brand or chinertown, but interested in upgrading the winter bike. I'm worried about top end frames and wheels disappeaing for rim brake.

So if i am after a BSA BB frame and super lightweight 50mm wheels for rim brake any recommendations ?
I've never worn out rim brake wheels and done enough alpine/pyranean decents to be happy with old tech. Why downgrade ?

If I swap over wheels my 2nd bike with 9 speed dura ace weighs in at 6.9kg for a 25 year old ally frame. Should I stick or upgrade.
It looks like the whole of the top end bike industry and chinertown suppliers are going disk, but disk seems to me a solution waiting for a problem.

If the only reply's to this query are "upgrade to be benefits to disk", then thank you very much, I' ll just stop reading the forum, as chinertown is not for me. i thought there remained a niche for high quality rim-brake...