i made my 9-jole and sump gskts. the gskt material is available. i use the covers to trace an outline, to mark the holes i just use an appropriate sized drill to make a mark. i have a leather puncher for making holes. then i take some 6 mm screws/bolts and hold the paper in place and using a hardened dowel (or drill stock will work) and firmly roll or drag the dowel against the paper along the interior aspect (sharp edge corner) of the cover in order to make a mark on the paper. afterwords i take a medium tip felt pen and trace the mark made by the dowel pin. i have a very old pair of high quality long narrow blade scissors for cutting the outline and start my cut on the outside portion of the gskt. for cutting the inside, i use the forementioned scissors when possible or else a medium size pair of nursing bandage scissors. for around the holes, especially on the inside aspect of the gskt, i use a pair of scissors called a curved iris (curved cuticle scissors.) for cutting on the inside, i start along side the interior edge, then cut exactly on the mark. my gaskets come out looking like factory.
you can buy a good set of scissors for general purposes about anywhere. nursing bandage and curved iris (cuticle) scissors, you should be able to get at a drug store.
without using these three scissors, a drill for marking hole position, a leather punch for making the holes, and a dowel pin to mark the inner aspect of the gasket outline, the job of making a gasket look good will be frustrating and the outcome unsatisfactory.