Copper Drain Pipe for shower

I took out an old shower basin to be replaced with a new acrylic shower basin and discovered a 2 inch copper drain pipe. So I couldn't use the drain assembly I had gotten that uses a rubber gasket for PVC or 2 inch cast iron. I was told I have to use a oakum and lead joint with the appropriate drain assembly which in this case turned out to be a brass drain assembly. My question is how hard is it to do one of these fittings? I've seen it done a couple of times. You pack the oakum on the bottom, pour the molten lead on top and then use a caulking iron to pack the lead. Is there anything special I need to watch for or watch out for? I have about a 2 inch space from the bottom of the fitting to the top of the drain pipe with which to fill. How much should be oakum and how much lead? And how hard do I have to pack the oakum and pound on the lead? How much room for error do I have? I'm definitely outside of my comfort zone on this, but I want to give it a go anyway. What are my options if it leaks. How hard is it to redo or make it stop leaking

shower

You could just get the gasket made for copper tubing. 1" of oakum and 1" of lead. You will know how hard to caulk it once you start.