Sorry to be late to the party...
http://www.amazon.com/gp/product/B0009OR93I
Ring compressor. Our pistons are tiny and light, the wrinkle style compressor gets a tight fit on the rings without being bulky like so many tool built for big fat cast American style pistons. Also, this one is very lightweight, has a small handle (which is important with all of those head studs in the way).
Worked a charm on my rebuild.
I also use a leftover 13mm wrench as a flywheel lock, even easier and faster than drilling bar stock
