The Kapex KA-UG Trimming Attachments work well if you take the legs off and screw them to the bench, and can also do double duty as material support on the MFT and CMS etc. They have measurements and extension arms built-in.
There is a thread on FOG where Lambeater has done this with a picture to help with visualisation.
http://festoolownersgroup.com/festool-tools-accessories/finally-mounted-my-kapex/
And of course, should you ever take it somewhere, or use an MFT or CMS "in the wild", you can put the legs back on and still make great use of them.