This response is really late, sorry to awake the zombie. I never followed up to share what I finally did.
I decided to try to keep the original Raleigh threads without re-facing the Raleigh BB shell, and used a TA 314 BB spindle. If it didn't work there was always the LBS with a thread-cutter.
Getting the original cotters out was a very hard job, but the original spindle was only a little damaged. I was, however, very down on cotters! I dug out my TA box o' crap and found the 314 spindle diameter fit through the holes in the BB cups, and that the distance between the TA spindle bearing tracks was the same as that of the original Raleigh Industries BB spindle. Therefore, the TA 314 spindle and the TA 5-vis 50.4 mm crank arms would (and do) fit into the Raleigh BB shell and bearing set. I tried it without a chainring to see if the crank arm ends both cleared the chainstays by the same margin! Next I bolted on a 46-tooth TA chainring (touring), and its clearance and true spinning were great! Later on I checked the chainring widths and decided I needed the wider Pista chainring to match the rear sprocket, which required a ⅛ chain. I found a 49 tooth Pista ring and now that's what I have on the frame.
Current steps are to install the "new" alloy rear rim (Wolber/Super Champion Modele 58 40/32) on the original 1952 AW steel hub, an alloy FM from 1954, or an alloy AW from 1953. The FM is my preference, but we'll see if I can get the indicator out to check it. It feels funny. If it's a problem I might just go with the alloy AW. I also have to lace and true the original front rim.
It's not about weight-weenieing, but I think these changes will reduce the bike weight by about 1 pound. I'll never actually prove it, however. The tires will be wired on Pasela Tserv rather than Dunlop Special High-pressure. I guess they are about the same. A Kalloy seat pin replacing a rusty steel Raleigh Industries post gets probably another 2 ounces, at most. So far all the other parts are planned to be original 70 year old Raleigh Industries.