Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Can't remember that either, but I know they leak all from the top if the wrong ones are used, so I guessed they can't be re-used. No doubt when I actually start the work, some of this will come flooding back!
To keep an awkward gasket in place I find a light smear of high temp grease helps.