[Steve Davis]

Hello Resipla, You can use two 10uf capacitors @ 450 volts. The two parts of filter capacitor number 50 are not conected in parallel. The negative ends are both conected to can, which is conected to the center tap of the high voltage winding of the transformer. Note the cardboard insulators on the cans. The positive ends conect, one on each side of the speaker field coil. I think there may be some confusion because the conecting dot is missing on the schematic just below resistor number 28. Resistor 28 and the the output filter both conect to the top end of the field coil.
Steve