Hi John

Most people just feed the slugs in using the existing entry to the mast channel. It means you then have to use some means of stopping them falling back down when you lower the sail. You can buy a slug stop which slides in and clamps with a thumb screw, although I've heard these tend to work loose and fall out themselves - usually overboard! A simple piece of line tied round the mast can do as good a job.

You don't need the channel entry to be as long when using slugs as opposed to bolt-rope, so you can partially close it. Judicious application of a wooden mallet will hammer it back to its original shape. Work your way down from the top until you've just got enough space to insert a slug.

On my 26X I closed the entry completely and cut a proper gate further up so I could drop the slugs in - probably what you're thinking of. I used a Dremel-style tool with a cutting disc to cut a rectangle, with a strip of aluminium angle to allow it to be removed and replaced. I've got a photo somewhere, I'll look it out and post a link.