When you use four threads, they have to total the diameter of two threads. The best method is to string the beads on a double thread and use the second double thread to pass through the beads one at a time and knot them. larkshead or overhand would both work.
The composition of the four threads can be the non-stretch threads as the stringing medium then the second 2 threads can be silk or Griffin beading thread-both come in many colors the right color or any other beading thread. Actually. Make the cord 8 times the length of the item, plus 10 inches. string it through once, put on the clasp and knot back all the way to the beginning and put on that clasp. ech clasp should only have two strings. There are a couple more details to tying the second end clasp, if you are interested.
I hate to ream, so when I get a thread that is too large to go through my end pearls, (You know I love that big bead, little bead thing -and often the little bead, if at the end, will not take the double thread twice. So I like to use the big bead at the end and even add an extra end bead which can be silver (or whatever).
If I can't find a matching bead smaller than the big bead, but bigger than the smallest bead, sometimes I will have to pass the threads through the clasp with the gimp on it , pull it tight and knot it immediately. Then I put a crimp bead on the knot for extra strength and then a crimp bead cover, which looks like a silver bead when put on and closed properly. I don't use clamshells because I do not like the look or the strength (none).
I will try to get some photos of examples today. I personally prefer to have two knots. When there is just one knot between the first and second bead, that knot could come undone and the item falls to the floor. So I like to pass it through the second bead and knot it between it and the third bead. No one has broken a strand done like that.
