Adjustable resistor question

[godi]

Hi every one.

I'm starting to build a 5E3 amp and I have tree newbie questions.

Can I replace the 250 Ohms / 5 watts resistor ( the one that set the bias ) by an adjustable resistor like this on on the picture ?
http://www.sphere.bc.ca/test/loads2/...-ar10-2500.jpg

This one is a 2500 Ohm, 10 Watt Adjustable and cost 4.00 $ at :
http://www.sphere.bc.ca/test/loads.html
I guess that it is possible to make the adjustment of the tap to be in the 250 Ohms range.

My second question is : I want to try a choke and see what it does to the tone. I understand that I need to remove the 4.7K/2W (or 5K/2W) resistor and solder the two wires from the choke where this resistor go. Many treads I read say that when a choke is use, it is wise to add a 470 Ohms resistor (or less resistance) on the power tubes. Witch pin number should receive those two resistors on a 6V6 tube ? And what about the other end of this resistor, does it go to the chassis ground or to somewhere else like to an other pin ?

Third : I did try to solder a 1 Ohm resistor in my Vibroverb clone Bandmaster amp chassis (for easier bias calculation and bias setting) but my Weller 100 Watts iron is not hot enough to make a nice soldering. What kind of tool do I need to solder something on a cold chassis ? Can I simply drill a small hole and screw a Grounding Lug ?

You can see some pictures of this amp at :
http://www.jeangodbout.com/vibroverb/clone-1-en.html

Thank you.

[Enzo]

SOldering to the chassis is hard. One thing it takes is patience, you have to hold the gun on there for a l;ong time. Far easier to mount a ground lug and solder to THAT as you suggested.

You could use that sort of resistor, but why start with 2500 ohms? You'd never use more than a tenth of it. Get a 300 ohm resistor or something. Imagine trying to change it ten ohms on the 2500? Now imagine ten ohm adjustment on the 300. 10 ohms is spread out a lot farther on the lower resistance part, a lot easier to get the setting you want.