Next, hang another plumb line down the front and back of each foil. Drop another plumb line down from the center of the transom. Finally, take another line and put it between two heavy objects (bricks work well), tensioned just above the ground and just kissing the bottom of the bow and stern vertical plumb lines. This will give you a good idea about the amount of work that lies ahead. From this line you can see if the appendages are vertical, parallel to the centerline, and in line with each other.
If you’re not interested in removing the keel to adjust it, which is probably beyond the time and skills of most people, then forget about beginning with the bow and just start by making the keel vertical. Follow the same process, with the plumb bob off the trailing edge and shimming the trailer, etc. You still need a plumb line hanging from the bow, except this time tape it to the centerline at the waterline and hang it to the ground. Basically, if you’re not going to adjust the keel, start with this as the fixed point and make everything line up with it. If you are more ambitious, then begin with the bow and work from there.