Will, that job is the one job in arborist splicing that I think is least fit for the Wand. Though I've done many a 16 strand splice with the Wand, it was too much of a hassle. I suggest using a wire pull fid for that last part.
Do you know how to check if you've snagged the core?
I think so. with the wand inserted you pull the exposed core strands and see if the core slides past the tool. sound right?
When i first tried to do this splice i used a wire fid (home made) but had trouble at the same stage. How do you attach the cover strands to the fid? thanks for your answers. wish id been able to ask these questions months ago!
grab some rope fibers leftover from a splice, preferably technora or vectran, but anything will do. Get 3 pieces each just thinner than a piece of dental floss. Now braid them together as tight as you can to the right length, fold it in half, tie a knot, and you're good to go.