Cornwall new terminals

I have a pair of 30 year old Klipsch Cornwalls. The terminals on the back are very small and I want to use large speaker wire. So I need to install new terminals. I have never messed with my speakers before, so I want to get myself ready before I start -- I have the following issues. How are the wires inside the box attached to the terminals -- soldered, crimped, a detachable couplng, etc? Do I have to take off the back of the box, or can that somehow be avoided? If I must take off the back: 1) is there a sealing gasket that I might need to replace? 2)is there any maintenance I should do while the box is open? Any other guidance or cautions would be appreciated.
Unless you want to take on a larger project, I found the easiest way to address this issue is to get a cylindrical spacer the width of the contact area on the terminal strip. Then, get two washers per side to 'pinch' the large spade, and a longer screw to hold it all together. Use different length spacers for the pos/neg, so they don't interfere with one another.

If you're using banana plugs, you could try these.