Unfortunately the B voltages don't seem to be shown on the chart for your model. If you wish to work with non-electrolytics at the original values, you can go with metalized film caps. Any non-electrolytic will do. Metalized film are the most compact, and tend to be the cheapest. Go with the 630 volt caps. If you decide to go with electrolytics, well, the only real way to economically spec them is to figure out what your set develops when operating. Unfortunately, by that point, you'll already have caps in the radio and working. You can take the AC output from the transformer and divide by .707 to get the peak value, but what you see at the rectifier cathode is rarely as high as the peak value, so you might overshoot by quite a margin, and that can add a little to the price. You'll probably be fine with 450 WVDC caps. You could even settle for that if you decide to go with non-electrolytic caps (as opposed to 630 volt caps).
T.