Sometimes - it's not what you see that counts.

Bead hole sizes aren't all the same - and it doesn't usually make sense to try and match them for a project. Sometimes, you are just going to have some beads that you want to string that just have much larger holes that the other beads around them. If you went to a thicker stringing material, then you maybe couldn't get the smaller-holed beads strung.

Or maybe, as is often the case with lampwork or other art beads - the hole is so large that nothing you are likely to string on is going to fill the hole - short of a fat leather cord.

Often - when you string a very large hole on a thin stringing material - the bead with the large hole won't sit straight, and will cant to one side.

There are a couple of approaches to changing this.

One is to put a bead next to it with a smaller hole, that nestles into the larger hole of the larger bead, and helps to straighten it out. Bicones, lentils and small rounds are wonderful for this. (See pic - note the 4 mm Swa. - sorry "Crystallized - Elements by Swarovski" bicones snuggle into the largish holes of the lampwork beads, and the sterling beads . ) I always keep a supply of the 2, 3, and 4 mm sterling rounds, for just this purpose.

But - sometimes this just doesn't work with your design - you might have something more streamlined in mind, and find this look too fussy. In that case - put the "straightener" beads inside your big-hole bead. Choose small seedbeads, or bugles, small metal rounds that fit inside the hole - unless the bead is clear - they aren't going to show. With the tiny beads strung inside the bigger bead - and usually you can find something that will fit - the big-hole bead will stop slopping around on the stringing material and will line up nice and straight.

A word of caution - string the small beads on the stringing stuff, and then try them inside the big bead hole. If you just try dropping them in the hole - they will probably not line up and allow you to string the bead - which will go from having too much hole to none at all.

Then you have to try and poke the offending bead out with a stiff needle and possible using some lubricant like detergent, being careful not to apply so much pressure that you split the large-hole bead from the inside out (in the case of lampwork beads. They are tough - but glass doesn't give!).