Re: Draining the filter caps
It's the resistance and power-handling capability that matter. Assuming a B+ of about 450 VDC, that 25K resistor will be dissipating about 8 watts for the short time it takes to discharge the caps. So, any 25 K 10-watt resistor will do.
You could also use a 50K 5 watt, but it will take twice as long to discharge the caps. Always make sure you check with a meter to make sure it's dead before starting work.