Since DD has made a few gaskets from copper sheet we thought it a good idea to add the info to a dedicated topic.
"what do i use to cut the edges? i presume you mean round the stud holes etc? SCISSORS

thin copper, where tin snips tend to curl it up. i ALWAYS cut the centre hole first, followed be the stud holes, followed by the final shaping

cheers, dd."
DD uses 0.3mm or 0.5mm copper sheet and cuts the centre holes for head gaskets using an adjustable tank cutter like this.
http://www.ebay.co.uk/itm/Priory-201-C- ... 2682744220
and says that "before you start you must screw the corners of the plate securely to a block of wood and make sure it's dead flat"
I am guessing a pillar drill very gently applied to the job would be best at cutting accurately.
Feel free to chime in DD if you have any revisions or further advice.