can i just tie the lines to the sails or is it better to use some sort of SS clips?
Yes and no. Maybe.
Lines have for centuries been tied to sails.
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.