follow this link: Running Rigging Calculator
Then use the drop downs to find your boat. It will tell you how much line you need for each sheet and halyard. Then put it in your cart and the proper line will be sent right to your door.
If you have any questions or if your boat isn't listed contact @Dave Groshong and he will help you out.
When you want to take the sail off the boat you need to untie the line. In a hurry you might cut the line. But then you need to fix the cut rope before it frays. Cutting line not a great idea unless in a real hurry.
Innovation make a metal clip (shackle) to tie onto your line, then you can attach and unattach the clip to the sail as much as you please. Metal fasteners come in all sizes snd great for halyard to sail head connection yet can be dangerous if the sail is flapping about in the wind (like a jib clew).
Enter the use of dyneema line strong as steel but light density and the soft shackle. Great for a jib clew to sheets but not as good for the halyard to head of Sail attachment.