I like to start with the Root over Rock trees because unwrapping those is better than Christmas. Roots and rock have been buried for a whole year so there's no telling whether any tree will be great or terrible.
Here's the row of ROR before I started. You may be able to make out the foil just sticking up above ground level. A good arrangement of roots running naturally over the rock is imperative with root over rock bonsai. Gaps between the rock and roots detract from the look and the roots should hold onto the rock so it won't move around. There's also the overall shape to consider. Trunk and rock need to give harmonious lines and shape.
All that means that there is plenty that can go wrong and make the whole project worthless - just a couple of roots that didn't develop
or one growing too large 
.........Tension builds.....Will it be good or not
Roots are holding the rock well on this one. Now that I can see the root and rock arrangement I can cut the roots back to just below the rock and then prune the top. This one looks good from both sides which is great because it will give more options for future shaping of the tree so I've left extra leaders for now. Decisions on which line to follow can be made depending on where and how new shoots grow this summer.
Here's another one that looks good front and back. That one was supposed to b a nice small tree on a small rock but obviously the tree had other ideas so now it will have to be styled as a larger tree on a small rock. That's one of the drawbacks of field growing - trees can easily get out of hand.
And finally another good looking root arrangement.
