Adjusting topping lift

[Seachelle]

Ahoy, CP friends! I've been taking a lot of video of sailing my Legacy and noticed something in one of the videos that makes me question I'm not adjusting my topping lift correctly. I've not loaded the video yet to my sailing YT channel, so I'll do my best to explain what's happening and show you a screen shot from the video (if I can figure out how to load a pic here). The situation occurred when I was going downwind, wing & wing. My main was off to the starboard side and I noticed what looked like a crease going from the tack and up about 5 ft at a position of what would be 1 o'clock. At the time I was sailing, I didn't really notice the crease, but now, watching my videos, I see it and I'm trying to figure out what I was doing incorrectly. I wondered if I had my topping lift adjusted too high and this was causing the crease. I am not sure where my topping lift is supposed to be positioned under sail — but I usually position it higher when we're in our slip so we're not hitting our heads on the boom while in the cockpit. Anyhooo... someone once told me (another sailor friend of mine) that the boom should be parallel to the water, so while underway, that's what I've been doing, or at least trying to do. i would be grateful for any feedback and suggestions — thank you so very much! 

Edit: Cannot attach a pic for some reason. Hope my explanation makes sense as such. 

[brackish]

 The topping lift should be slacked when under sail and the sail itself will hold the boom up.  If your boom is lifting when you are running downwind you need to add a boom vang to hold it down.  If your topping lift is too tight it negates the sheets ability to control the sail.  So when sails up, topping lift always slacked so it is essentially doing nothing.

[Seachelle]

The topping lift should be slacked when under sail and the sail itself will hold the boom up.  If your boom is lifting when you are running downwind you need to add a boom vang to hold it down.  If your topping lift is too tight it negates the sheets ability to control the sail.  So when sails up, topping lift always slacked so it is essentially doing nothing.

Hi, brackish!

Thank you so very much for your feedback — it is really helpful!

All the best!
~ Chelle and SV Sunny
https://sailawaywithchelle.wordpress.com/