Sounds like you've got a nice project amp.
Here's a great place for loaded boards with high quality parts. They even let you choose between orange drops and Mallory caps.
http://www.turretboards.com/
It's fine to use an 8-ohm speaker. It might not sound as good as the 4-ohm, but it won't hurt anything.
Your amp tech can tighten the tube socket. That is a very common issue.
As for being surprised ... that depends on the price. If it wasn't heavily discounted, call the guy and ask for money back to pay the tech. You're looking at some fairly expensive repairs.