No use re-inventing the wheel. We sell them right here on our www.OnLineMarineStore.com
Here is the link
https://store.catsailor.com/pc/viewPrd.asp?idcategory=0&idproduct=8165
For sidestay and bridle wire I think cassette tape is too light and dithery. Best is old 8-Track. It is light enough to respond to even the lightest winds, yet doesn't jiggle all over the place like cassette and make it hard to read. I have some really fast stuff -- Abba! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Or you can go to Radio Shack and get reel to reel tape very cheap and it is the same size.
Rick