Cutting rubber sheet.

[Pigeon_Droppings2]

As above...I find it easier with rubber to do 1 smooth continuous motion....you can stop and reposition but hold the knife where it is.

For the holes I reckon a press cut would be neat....but you might get away with a very fine hole saw if you sandwich the rubber firmly between 2 sheets of ply.

 

[winchman]

You can buy Circle cutters from Craft places not expensive