On a PS I built, using 240V, i used a 50 ohm 50 watt on each leg. Then I used a time on delay relay to kick in relay and bypass resistors. I have 300,000uf of capacitance in line and needed something to take load off when starting. At 10 amps, dpending in circuit whether for a filament, or rectifiers and filter capacitor used. Yu could use a 50 ohm, even a 25 ohm and with a 10 A circuit use a 10-25 watt resistor. Depending on how long of a delay. As longer delay will cause more heat in resistors. Hope this helps.