Can you?

Yes.

Yup I’ve got 700×32 on my CX bike(29er rims)

28mm Conti GP4Seasons didn’t want to go on some 29er Crests. Mental tight.

What rims do you have?

Er not sure, they are in the boot of my car some 1,000 miles away 🙂

Bontrager somethings.. Ryhtmn Elite…28mm I think

Yes

Yes.

Same rim diameter so it all comes down to width of rim and tyre. 32mm and up will be fine on most XC rims

you need to be a bit careful – some 29er rims aren’t built to handle the high pressures of road tyres and may fail in use.

Iwas thinking of the Schwalbe Winter marathons, they are 40c I think

You’ll be reet. Good choice too. You soon get used to the noise, especially if you like popping bubblewrap 😆

As with all there are some rim and tyre combinations that are a git. Stans arches wouldn’t take some Kenda small block with more force than I was willing to try.

Yes

Yes, I run 32c Small Blocks on my Arch EX rims.

28mm Conti GP4Seasons didn’t want to go on some 29er Crests.

You just weren’t trying hard enough/doing it right. 😉
I’ve had 25mm Gatorskins and GP4Seasons on mine and now I’ve got 28mm Schwalbes fitted.

I desperately want to bring my bike out here to Sweden but I’m not sure it’s appropriate for business travel.. 🙂