True. 7mm Bzzz Line (what I used in the prototypes) has a rated tensile strength of about 1700 lbs. 1/8" Amsteel Blue (the dyneema line I used) rated minimum strength is about 2300 lbs. Even if the knots cut the strength in half, you'd still have a 5x-10x safety margin. Therefore, I think any of the three would be practical.

I like the red pigtail because it is the neatest and smallest. It must, however, be spliced directly onto the sheet. If it ever wears or is damaged, the pigtail will need to be cut off and a new one spliced on.

The advantage of the green version is that the strop can be made separately from the sheet (see below). It can be attached or removed later. When it wears, the strop can be easily replaced. You could even carry a spare and swap it out on the beach. If you aren't comfortable about splicing dyneema yourself, someone else could make the strop for you without you having to send them your sheet.

I made the blue one because I wasn't entirely comfortable with how the others will tend to open up the braid under load. That can't be good for the line and might lead to hidden chafe. The strop is very easy to replace on this one. Unfortunately, it's bulky, and the brummel might not be easy to tie, depending on what line is used for the sheet.

Regards,
Eric