:agree:
In addition to keeping the bike from moving forward, you want to stabilize the front wheel without compressing the shocks or endangering the fork seals. There should still be some travel left on the front and rear shocks.
Tying down by the risers works fine - as an alternative, you could loop the tie-down strap around the fork right on top of the bottom triple clamp, around the inside of the turn signal.
For the rear, it's a little tough for tie down points, but the back of the bike should certainly be stabilized in some way to keep it from hopping around if the road gets a little rough. If nothing else, put a strap across the width of the trailer going through the rear wheel, holding the rim down.
Very nice work on the trailer, looks great and fits the bike fine.