It might work though.
We built our own track for this year and this is how we eliminated the tension problem and also how we ensured all lanes were equal and level.
We cut two equal size face plates 1 for the starting line and the other for the finish line. We clamped the plates togeather and drilled three equal pilot holes through both bords. These pilot holes are for your threaded hooks and eye hooks. On the starting line end use the threaded hooks and then use the eye hooks for the finish line. Tie your fishing line to the hooks and then thread it through the eye hook, at the end of the line tie on a S-hook. Make three weights the are equal and hang them off the S-hooks pulling the fishing line tight and equal.
This way if your track shifts or gets bumped the weights will still keep equal tension on all lanes. But make sure the weigt is equal and that each lane has its own weight.
Also we found out real quik, make your track 60 feet long. A will made ship will diffently travel that far.
Good luck and have fun
We built them out of 2 x 4 lumber (in some cases 2 x 8 ripped in half that I had around). We followed the plans in the Leader Guide. For the side braces, we put the screws in the sides to allow for them to collapse by simply removing the rear screws and they collapse. By the way, I think the angle to cut the legs is 21 degrees - used math on the lengths to figure it out (Oscar Had A Heap Of Apples - for the engineers out there).
Anyway, let me tell you, they are really sturdy. Personally, I would not use 1 x 4. Just use 2 x 4, and following the leader plans, it is really easy. I could build one in about 2 hour using their plans now. All straight cuts with the exception of the leg angles. I used a drill press for the dowels to make sure they looked good and straight.
For the weights, for increased tension, the weight should be on the bottom of the back legs. Think about it, to get the most torque around the moment arm, it is better to be away from the rotating point. The Pack 80 plans with the bottles hung from the center do not maximize force in my mind. Sand Bags would on a cross in the back bottom would do better.
Regarding the tension on the lines - They clearly recommend using hooks and lacing all 4 lanes to make sure that they are all the same tension. Ours seemed to work really well. What we used are eye hooks, and the boys used the vice and a crescent wrench to open them up to the side to make lacing a breeze (sort of like lacing the top of your boots with the open hooks). What I did was took three boys aside and asked them to figure out how to get the line through the eye without threading it, and showed them the difficulty of lacing it on the course. Told them that they could use the crescent wrench, and the vice. While a couple got close, not one got it. But, after seeing it, they all thought it was neat. After building the setups, they are all proud of how to lace the course fast.
Now, I do have a question. Have heard that some line is better than others. Any suggestions? Will continue to check this site and others out.