The very nature of the contact cements is that they can not be moved around after contact ( thus the " CONTACT" ).
So on large cumbersome items you may need to have a helper and or some devices...
For instance, when wanting to glue large pieces of leather together which must be aligned contact cement can be applied and then a large piece of waxed paper placed between the pieces... then you start at one edge and push down on the leather as the waxed paper is withdrawn from between them.. this keeps air pockets from happening...
For hood pads something like thin plywood could be used to place the pad on and two people raise it into alignment .
For some things extra hands are almost necessary for enjoying a project....