Having lashed on the warp and gotten it evenly tension, I proceeded to throw the shots necessary to align the warp ends evenly.
Two sets of crossed warped ends. These were easy to correct. I was able to cut the ends off close to the knots. Then I resleyed the ends in the correct dents so that they no longer crossed.
Next I tied on an extra length of warp to the two ends and, in each case, tied it onto the lashing cord.
The next problem was more serious.