I have used a carl paper trimmer but now I use a score board I bought off ebay.
Manual table top Professional Scoring Creasing / Creaser Machine – 14¨capacity was the title. And I really like it. It has guides that are not just magnetic – you screw them down with hand screws and it keeps them more stable! I paid around $170usd
And its a one motion score not like the carl which you had to lock down and then run the wheel across.
So far the only annoyance is I wish that it had a little more space to slide the paper in (and for me I wish it was much smaller! it is HUGE!)
Angela
Ladybug Press