Is it possible to designate "registration marks" to 25% opacity?

[ajrunke03]

We have a job where I can't offset trim marks. To help lessen the visibility of the trim marks due to inevitable press wander, I'd like to screen back the opacity of the marks to 25%. When selecting the swatch "registration", is there a way to designate the opacity without doing it manually?

[Monika Gause]

You have to make them manually then. 

[mjbelt]

Try making a symbol. There is an example in Symbols Panel.