I'd value your opinion Kev,do safety matches offer a different tone from the good old cheap red toppers? The colour of the elastic bands would be a concern too.
In my experience Davy, safety matches offer a vintage sound, the other cheap red topped things are for EDM and suchlike, the thickness of the band is extremely important if you want to avoid a boxy vocal...too thick and it resonates in the 200Hz area, too thin and you've got problems in the midrange area, although the amount of stretch comes into play and depending on the room it can get quite complicated,
then there is a significant problem if you have a snap in the middle of a session...matchsticks have to be re calibrated and it can take a while to sort out a suitable elastic band so's the sound is similar...and you gotta wait until the singers lips recover!!
then there is the bend factor of the matchsticks which can only be done with laser equipment, a whole other story.
I don't do this bit because it's too expensive
all this is a lot of trouble but cheap! cheap! cheap!!! your much better off if you are rich and have a microphone....
I'm using a vintage elastic band from the sixties, ( with 4 knots in it which seems to add to the vintage vibe) I got lucky and found it in the attic...must be worth..oh, at least 20P
anyway..busy saving saving up for a Mic....
cheers, hope the explanation wasn't too technical for you mate..
best, Kevin.