forest farm in oregon seems to have the species in stock:
https://www.forestfarm.com/
(i am not affiliated and can’t vouch for them)
i have one of three surviving C. colurna that i’ve had for maybe 6 or 7 years…can’t remember where i got it, but i’ve searched through the possibilities and none of them have them anymore. the one, while it’s never really struggled, have moved pretty slowly. it’s currently about seven feet tall, all growing from a single trunk. so far i’m pretty unimpressed, but it’s just one (or three if you count the dead ones) data point…
no
experience with that hybrid.