On the IIC+ & III Coliseums, the half power switch is a 22K 2 watt dropping resistor that lowers the screen voltage about 100 volts, drops total wattage down to around 50.
There are both KRG (180W) & KDRG (120W). The KDRG is the odd Mark that the MIDDLE pair is the Simul pair and can take 6L6...