For free floating jugs, I used to use 3 inch thin walled pvc with spray foam as a float but it is a lot of work and don't think I would do it that way if I need to build . I would recommend 3/4 inch pvc which should fit into a swim noodle. Cut them about 10 inches long or so which should give you 5 jugs per noodle. Slide the pvc into the noodle and wrap them with white duck tape as tight as possible to give the noodle strength, make it white which is a legal requirement, right name and number and address and date on them. Drill a hole through the width of the noodle/pvc about three inches from one end. Thread a 100 pound black tarred string (you get it from walmart or academy but has to be the black tarred string not white nylon or non tarred). Tape the string to a small rod and thread it through the hole you drilled through the pvc/noodle. The pvc gives it strength which is why i add it plus cheap. Once string is threaded through the noodle/pvc, tie it directly to a trotline clip. Pull tight and start wrapping it and put a good 50 feet on it or way more than you need. If the string every comes off you will not use your jug because it is tied directly to a trotline clip and cannot come off. You can tie one or two hooks to the end of the jug and I do not recommend using any swivles or any three way rigs. Just put the top hook and loop the string with a 4-6 inch loop. Every once in a while a fish will twist but it rarely effects it and you can retie it in a minute. Swivles always made a bigger mess than it saved me on free floating jugs. Add a 1 ounce round weight above bottom hook. This system allows you to adjust your depth on the fly by letting out X amount of feet and then using the trotline clip to clip back to the string and set the depth. I eventually want to make a youtube video over this but haven't found time. This system works awesome and catches fish! I have made the flagging juglines and I honestly can not recommend them. The delayed reaction seems to cost me fish versus the fish grabbing a jug and pulling the whole float down. Just my two cents but hope it helps. You can fit about 10 of these jugs in a milk crate sized container. I'll try to make a video in the next few days to help give you a visual.
RespectTheFish on YouTube