I had Nextie Jungle Fox 50mm (42 internal) carbon rims and they were ace.  Light for their size too at 530g.

I tended to run 10-12PSI front and 14 in the rear.

Thank god Stans Hugos are discontinued. I had several, warranty replaced many times, all failed at the spoke nipples and dented irreparably so so easily. Rubbish!

Anyway, they are gone, so good news! To replace I got Lightbicycle 50mm carbon rims. heavy duty ones (heavier, more material). Been superb. These fellas will sell you a pre built wheel as well.

Not answered many of your questions, soz!

Velocity Dually’s are the answer. Been running them on Hope hubs on the Singular Rooster with 3” Chronicles first and now 2.8” Teravail Coronado’s, both of which are fine in terms of shape. The wheels haven’t needed touching apart from a new set of bearings front and back after about four years. Fit and forget.

I got some Easton/Raceface ARC 40s built up on Hope Pro 4. Been running these with WTB Ranger 3″ tyres on my Krampus and they’ve been great.

Also have a look at sun ringle duroc 50’s great plus rims, and tubeless up super easy.

Another vote for Dually’s here.
Right now I have a mix Dually rear and Halo Vapour 50 upfront, can’t fault the Vapour but the Dually has really proven itself. It’s been on various builds and taken a good beating over the years but is rock solid, some good dings in it but no issues with any tubeless setup. Nice simple look to them too. Not that fond of the etched graphics on the Vapour.