There have been extensive discussions of restoring Mac tube gear here. Many of the discussions, though not specifically about the MC-60s, apply to them. I'd suggest you start with the Hints and Kinks sticky here then do a search for tube amp restoration.
Many of the discussions will assume you know and understand what a bias circuit is, what a power supply is, what a coupling capacitor does, what a filter capacitor does and the various sizes and values of components they have.
You'll also see references to various brands and types of capacitors plus discussions and opinions on their sonic merits. It can seem overwhelming at first.
As for kits, there are no full restoration kits for the Mac amps that would contain step-by-step instructions for each model. The demand just isn't great enough. This means that you'll need some understanding of how to read and apply schematic diagrams in order to work through the process of replacing the right components with the right new ones. There are people here who can help you if you take lots of pictures of what you're doing and are patient with those 'arm chair' bench techs with lots of ideas on what to do next.
Lastly, if you do want to do the work yourself, that's just excellent and many have found it to be a satisfying experience. I would highly recommend you get the proper test gear to do so, though. You should also be comfortable working with high voltages and have the proper test leads to handle it. I don't mean to scare you off but these voltages can be lethal. I've been working on tube gear since the 60s and I still get bit occasionally, so its part of the experience.
Hope that helps.
Cheers,
David
