A 425 on a 404 case would be nice but not much different from the 404 as far as capability goes.
Funny, I passed on a cheap 350 Rigby a couple years ago because the stock had been altered for a sidemount, low bolt and had been shortened. Now this one shows up with a very servicable stock. Between the two, there wouldn't be five grand into a very nice, although non-original, 350 Rigby. And, since I just traded my good one off....oh well...