Looks good now! A 450 volt can cap will be fine as that voltage rating is still well above the actual turn on surge voltage. Assuming you are using the same power transformer, it will work with an 8600 series amplifier, but the actual B+ voltage levels produced with the above configuration in the 8800 amplifier of this project are 310V, 305V, and 275 volts -- not the 255, 250, and 240 volts shown above. Therefore, for use with an 8600 amplifier, you'd likely want to keep the rectifier tube for the added drop, or add an appropriate resistor between the output of the diodes and the first filter cap, or possibly both. If a resistor is needed, it will need to be determined experimentally.
Dave
Dave