Fish,
dpending on your string material you will get more stretch. i use b50 that stretches an inch to an inch and a half, i buy the cheaper stuff, i think you can get prestressed? a lot of guys argues about the number of strands, but better to be safe and add a strand or two more than you need than the other way, just keep the strand even and don't go more than 7 strings in one strand. I know it gets a little more complicated when you start go three sets of 5, instead of 2 sets of 8, but thats actually safer (once you get over 7 strings in a strands, then some of them will not be doing equal work and you will actually have an underweight string)
all that aside, i don't use jigs...i pull off the first string 10 inches longer than the nocks of the bow on both sides, this will give you a little waste but not much, then cut the rest to match. I i make the first loop at least 8 inches from the end, this gives me plenty of strand to work back into the string, and room to taper it down. don't be tempted to twist it too much, i know it looks good, but the less twists the stronger, really.
when it comes time for the second loop i just start it the width of my hand below the second nock. i leave the first loop nocked that way it won't move on you, and is stays a good reference for length.
some folks say to leave a little gap between the regular twist and the second loop, but i don't like it. i just keep twisting the same all the way up to my second loop. mark where i want it to start, then twist enough length to make the loop on top of that by actually wrapping it around the bow once to check, then i line up the colors, and insert on of my arrow shafts between the strands. by inserting it in the hole of the twist between the 2 colors (of the full straing portion that you are twisting back into) you can keep it seperated. then one color back onto itself at least two wrap, then the other color on itself 2 wraps, pull out the shaft, and move it down one twist (once again of the full string portion moving back toward nock one), i repeat this untill i have two wraps back into the main string, in each of at least 7 twists. I don't even try to taper the second wrap back into the main string, i just serve it. i also pad the loops, by serving. some folks say it is too heavy and can be measure in grain weight, i just like the durability
does this make any sense?