As per Fordgtlover's post - i'll have to use the 370DAX series for the universal voltage - wiring it for 115v here and changing it to 240v when back home next year.
So will appreciate when the build comes to learn which appropriate secondary wires to use. I presume that 6.3v CT means that it it 6.3v-0--6.3 and we will use the center wire as the reference ground?
It's pretty easy to put a DPDT switch on the primary of the transformer so you don't have to actually rewire the circuit each time. However, you have to be really careful about flipping the switch to the wrong setting.
Chokes - chokes are great in tube PSs. I've used many of them myself. But be careful to think through the DC resistance of the choke. The two resistors R7 and R8 are calculated to drop a certain range of voltage so the the input to the to the regulator is high enough to keep the regulator regulating at 250V. The Hammond 158L has an R of 411 ohms. Depending on exactly how you use the choke this has to be thought through.