is it generaly o.k to reuse the base gasket when replacing the headgasket? do you need to use a special ring compressor when you pull the cylinders off or do you just work the cylinders over the rings?
Yes, you can reuse it. Clean it very well, and surfaces, and coat with very thin layer of RTV. Or copper coat spray, Gaskacinch. Some folks use spray paint, but I'm not brave enough. You can also leave it out for a bit more compression, if you have the clearance.
The rings can be worked in to the cylinders with patience and a blunt edge, wood or plastic. Be careful that the oil rings are butted before they go in.