Shock absorbers for guy lines Big tent

Ordered some shock cord hooks from New Zealand and they arrived today
Just a short question on safe stretch limits of cheap shockcord [ Good quality but not yachting stuff] is allowing 3 times a good limit
If I cut the shockcord 200mm long and cut the limit tape at 600 for instance
http://www.ebay.com.au/itm/131402077610 ... EBIDX%3AIT
8mm shockcord and 10mm polyester binding tape with both fit and nice and tightly too
Or should I allow more shock absorbtion and go 300mm but with less stretch so still 600mm safety tape?
Once assembled these are apparently very hard to get apart so it needs to be reasonably correct first time
This is for the big Geodome tent for the winter camp
Just a short question on safe stretch limits of cheap shockcord [ Good quality but not yachting stuff] is allowing 3 times a good limit
If I cut the shockcord 200mm long and cut the limit tape at 600 for instance
http://www.ebay.com.au/itm/131402077610 ... EBIDX%3AIT
8mm shockcord and 10mm polyester binding tape with both fit and nice and tightly too
Or should I allow more shock absorbtion and go 300mm but with less stretch so still 600mm safety tape?
Once assembled these are apparently very hard to get apart so it needs to be reasonably correct first time
This is for the big Geodome tent for the winter camp