I watched the video and I didn't see anything in that looked like it would increase the tension of the fabric on the top. Now I have done a convertible top it was on my wife's 99 mustang, of course I did a lot of research on the subject which included different brand vehicles, and the fabric pretty much fasten to the frame for the top the same way for all the vehicles that I looked researched. Now I don't know what the condition your top is so its up to you if you want to do this. Now the fabric gets the tension basically from how far it is wrapped around the front header on the top. But here is what you can do, put the top up and lock the back of the top down like you normally would, now take the front of the top and put it so it's at about 90 degrees pointing up, now you need to remove the rubber seal the seal should just pull out as long as nobody decided to glue it in and then remove the rubber seal mount and any other screws or parts that look like they would interfere with the top been pulled forward. Now after you have all the things removed you will see that the top is stapled now before you take out the staples take a wax pencil or chalk and go over the front edge were the fabric wraps around the frame, now remove all the staples and then slowly pull the top loose from the header you will all so see that it is glued but it should come loose. Now with the front of the top pointing up at 90 degrees pull the top around the header about a half inch past the old chalk mark and use some alligator clamps to hold it in place now put the top down to the windshield and see how the tension is repeat this till you have the tension you think is good keeping in mind that when the front is locked down it will increase the tension a little more, once you have the tension you want take your wax pencil/chalk and run it across the front were the fabric wraps around the header. Now put the top back in the 90 degree position and remove the alligator clamps pull back the fabric and spray the header and the back side of the fabric with headliner glue following their instructions 3m makes a good product then pull the fabric back around the header to the chalk line you just made and smooth it out, once you have it set re-staple in place (if you don't have a air powered stapler you may want to buy or rent one it makes the job much easier) after you get it all stapled you can reinstall all the parts that you needed to remove once it is all back together lock the top down and leave it locked down for 2 weeks straight this will help re-stretch the top so it locks down nicely. Be very careful when you do this project and take your time to make sure when you pull the fabric you keep it straight as possible, if you think that the fabric might be to fragile don't do it you will be better off with a new top or deal with the sag. I hope this gives you some insight.