I think you can get the 750VCT transformer to work. If your not dead set on a choke input filter.Go back to the example that Damir posted.(how do you do that?) Change the transformer voltage to 275, then tinker with the value of the first cap. As you slowly increase the value, the output voltage will rise.
With 10uf I was able to get ~365with 5Y3’s 10uf- 10h- 50uf With a 70ma CS...John