[suicideneil]

I used a pair of pliers to tighten mine when I had some- you can buy cheap socket sets at DIY stores for a few quid so thats the easiest option.

The shims should go inside the 23mm hex, between it and the nyloc nut that holds it in place. Beware though, as once they are on, they are a bitch to remove without using a fair bit of leverage force.