Looks nice. I like that you didn't waste material in long backsplices, which are often called for.
I take it that you are going to wrap it around a stem, then lower yourself from the pulley? Even though this should be safe enough, you may be pushing closer to that 1K WLL than you think. If your loopie were wrapped around a more-or-less horizontal limb, then the whole 1K would be available to you. No problema. But wrapped around the stem is another matter. You are applying a vertical load which the loopie has to absorb from some unfavorable angle. This can greatly magnify the force on the loopie. Using a loose wrap helps with the angle, but makes the sling more likely to slip. You can't win. Add to this scenario a heavy climber and a jerky descent, and you could easily push right past the WLL.
I frequently use loopies for this and similar purposes, but when a horizontal wrap is involved, I like to use 5/8 inch rope. I can wrap that as tight as I like and still feel confident that nothing I do is really going to stress the rope.