The AplineBF has advantages. Then only one end of the rope can slip with a bad lock (safer) and like Bodean mentioned, it keeps the ends closer together so that klemheist will hold when you get up there.
I do this with the climbing line while the throwline is attached so a mid-line knot is needed as well as the biner for mid-line clipping on to the throwline.
After the throwline and harrison rocket clipped into the spliced climbing line (with a small ISC gator) go over the desired crotch, I put a small loop AlpineBfly in the climbing line and clip a normal locking biner to this loop. Then clip the biner around the throwline and keep pulling.........
Then the gator, rocket, and climbing line will all pass through the biner coming down while the biner and AlpineBfly go up.
Ok, maybe a pic would be better.