I then started (very slowly) to edge the two pieces of my veil. I stuffed up a few times with the result that part of the hem would hang out, but i just unpicked it and started again. I edged the whole U shape, and left the tops undone.
If you're going to put any embellishments on the veil, such as crystals, i'd suggest do it now. I left it until after i'd gathered and attached to the comb, and it made it harder to do. Tulle is very tricky to get bead glue to stick to, and i ended up having to put glue on the crystal, place it on the tulle then press it to the floor (the glue comes off my floor easily), which meant i could only do a few at the time because the gathering made parts of the tulle come off the floor.
Once the crystals are dry, take your two pieces of veil back to the machine and sew two rows of gathering stitch (longest straight stitch your machine will do) along the top of each piece about 3-4mm apart, less than 1cm from the top edge. Then take the two top threads and pull the material away from them, towards the middle of the veil, to gather. Below is what they look like, before and after gathering.
Whipstitch them individually onto your comb, knot off the long threads at each end, then trim the top carefully, making sure not to cut any of the stitching holding it on. If you're like me, go along it with another row of whipstitch after you've accidentally cut some of the stitching :)
I was originally going to go over the whipstitch with some ribbon, but i've used very fine tulle and there was no way my ribbon was going through it. So i used a few crystals instead. I'll put up a pic of the finished veil when the glue is dry.