The beads are actually different sizes in the packet and not all really round. Average about 3mm in size. Of the top of my head can't remember the brand I used but they are poor quality stainless because I use a magnet to collect them out of the old tyre to put into the new ones. Don't see any rust on them though from introduced moister from airing up.What size beads (diameter) do you use Dan?
Do you have a preferred brand?