Titanium road & gravel bike...wheel/tire question

I'm in the process of ordering a new Ti framed bike, with versatility as a goal. For a few reasons I've decided to purchase an Alchemy, either the Ronin Ti, or the Chiron (Ti). I'll be doing a lot of asphalt bikepacking (typical load: about 8-10lbs of pack weight), and some gravel riding. I'm not interested in MTB type terrain, as I would use my MTB for that. I've ordered the Ronin Ti with 32 Conti GP5000 tubeless, and was planning on a second 650wheelset, with maybe 45mm tires. The Chiron is described as more of a cyclocross bike, and has a max allowance for 38mm tires.

Aside from any personal experience advice, I'm curious as to what the maximum recommended tire width on a 650c wheel might be for the Chiron. Would it still be 38mm as specified for a 700c setup, or is the restriction based on overall wheel/tire height, and not so much on width, allowing for a bigger tire? (I wasn't able to get a clear answer from Alchemy)

https://alchemybicycles.com/product/ronin-ti/
https://alchemybicycles.com/product/chiron-carbon/

Thanks, Roy

 

(...give or take, a 47mm x 650b tire has the same outside diameter as a 28mm x 700c wheelset)