I have also been painting Leaves from our garden with PMC Paste and absolutely love the result. After a little experimentation (ok - disasters!!) I did manage to produce a few pieces I really love. I discovered that the best result came from a really thick, well veined Leaf.
This Leaf (above) was an early attempt. It looks ok but is quite sharp at the edges and I probably didn't make it thick enough.
I was really pleased with this one (above). The detail is great and I managed to smooth the edges nicely. It is a perfect replica of the original Leaf - only in Silver!