Might be worth it to revive this thread as not much is being discussed about Hasselblad long lenses.
I now have the CF 350 and APO Tessar 500, and considering the Variogon 140-280.
There is no way I would recommend skipping the 500 over with a 2x + 350. This is not to say the latter has issues (even if it does). But the 500 with its tripod mount is superbly better on a tripod.
Conversely, the 2x + 350 with NO tripod mount is basically a hope-and-prey nothing will crack when tripod mounted on cameras plate. I’ll set aside any talk about reduced IQ, as in many cases this is not an issue, except how it handles and how that directly affects effective end sharpness.
Neither lens is hand-holdable, even the 350. The long focus throw alone makes it nearly impossible to get the intended sharpness point, as even for far away subjects the small movement of the kit in one’s hand will indeed shift it sufficiently to see a difference, be disappointed, throw the lens away, and start drinking again.