Wicks, bought or DIY, are easy to feed into most lighters. They have to be a bit tight to work right. I usually tie a bit of thread or dental floss very tightly very close to one end, stuff the thread up through the hole and then use it to pull the wick in, trim the thread off and fluff out a bit.

Making a wick from cotton string is simple once you know how thick you need it. You could probably get by just twisting up the cotton string. I plaited the few I made. Once you get the rhythm down it is about as easy to braid or plait up three feet of wick as it is to just produce the three inches you need. The only reason I needed to do it twice was because I couldn't find the remainder of the first go. Plaiting, depending on how tight you do it, can make a nice tight wick that pulls naphtha well, burns slowly and evenly, and produces a nice flame.

It isn't rocket science. It's screwing around with a ball of cotton string. Look up plaiting and braiding on the web and get yourself some string. Making your own light line is a useful skill that allows you to make your own string, light line, and rope. Also wicks for oil or fat lamps ... and a new wick for that oddball lighter.