I sieve at this stage for a perfectly smooth result and then pour into 2 small jars or 1 large. There is often a little bit left over from 1 large jar, but I just keep it in a small bowl in the fridge and use that up first. Recipes for lemon curd often use a bain marie to cook the mixture over a saucepan of simmering water, but my mum never did that, and it seems to work perfectly, so try it and see.