Nuts and bolts newbie question

So I finally got around to learning how amps really work and I have a few questions.

I bought a bias mod and bias probe from Mansfield guitars and a full set of KT77s from Eurotubes for my Stiletto Stage I. I have not yet installed the bias mod.

I have been researching and reading for 2 weeks now and there are a few things that are eluding me.

1. When I bought the Stiletto retube kit how did the guy know what tubes to send me?
2. He did not write anything down about mA settings. Is there a recommended mA for Stilettos with KT77s?
3. Let's say I buy a set of tubes the are matched but not specifically for a Stiletto. I need to rebias correct? I assume the amount of current being pulled by the tubes is how to determine the correct bias settings?
4. I have tried to get the DC voltage by using the pin 5 to ground way and my meter reads 0. What am I doing wrong? I left the tube plugged in a ran a wire off of the 5 pin.

If there are some sites that can answer these questions feel free to link and not retype.

Thanks,
Donnie