While there are a variety of opinions about the best (or cheapest) ring compressor I decided to use a HAZET 794U-3.
This type has a steel band that is detachable at one end. You place it around the rings, adjust the knob for the bore diameter and squeeze the handle, which compresses the rings. The cylinder is then pushed down over the rings and the strap slides down the piston skirt. Once the cylinder is covering the rings, the strap is detached and the compressor removed.
One thing I observed in using this tool is that it's asymmetric e.g. the band is deeper on the bottom compared to the top.
You can see the difference. If you try to use it "right side up" the base of the cylinder will hit the handle of the tool and cock the piston in the cylinder. As a result, you get half of the ring in and the other half pops out.
I had success using it "upside down" with the long portion of the strap pointing toward the ceiling. This allows you to very precisely compress the rings, slide the cylinder down so it contacts the raised protrusions in the strap, and nicely fit the cylinder. If a ring pops out, you can actually unclamp the band, slide it back up, re-clamp it and then complete the installation.
Success! (not that you haven't seen pistons before, I am posting these as a reminder to myself that in fact the INTAKE valve reliefs are on the INTAKE side!. The yellow stuff is Aeroshell Fluid 2F preservative oil, it will be removed before sealing up.
