Prices certainly have gone mental. I'm very biased as I own a full set Zenith, but I think they're almost certainly the one to choose over the later versions. I also think in the longer term they might even start to command similar sums to some of the older 6263 types as they're bigger and more wearable on the modern wrist.
I wonder if the next Newman watch might not be a Rolex at all. Maybe it'll be an Omega....
Here's a pic of mine. (My one lucky buy/hold after a load of regrettable sales of 16750s, an Ed White, a 60s SM300 etc.) We all regret selling watches we once owned, but it sure is nice when one you own shoots up in value. I think I paid £6750 for it, plus a full service. I'm a bit nervous to wear it now though as it's so minty I worry I'll ding it.
Good luck with the search for yours OP.