Pete, I'll field the Q, pending a better response from Gary (Hifigeek). Adjusting bias on the VS-115 is simple, safe and fast.
First, buy a Radio Shack multi-meter with test probes.
Second, if you're biasing brand new tubes, turn the bias pots down to mimimum voltage. Drop the new tubes in and let them warm up for about 45 mins to an hour.
If your setting up new tubes, they should be matched pairs because only one tube of the pair is a set tube. The other is a slave.
Then click the multimeter to volts. Insert the probes into the set tube insert openings in the back of ther amp and carefully and slowly set the bias to 65 mVolts. USE THE PLASTIC SCREWDRIVER THINGY ARC provides. DO NOT USE A METAL SCREWDRIVER.
Then check the slave to make sure it's bias voltage is within spec, which is betwen 57 and 73 mVolts. Repeat the process for the other 3 sets and you are in business.
Hope this helps.