The guys over at Serellan have given out some information to help out modder/mappers in advance of the mod tool release. The community over on the official Serellan forums has also chipped in ,So in no particular order here goes.
-The best version of UDK to use to aid in a smoother transition to Takedown is
Version: 9505 Changelist: 1174198
February 2012 UDK Beta
-When modeling assets for the game, Takedown is using the centimeter scale: 1cm = 1 unit in your modeling software. (so ideally you will set your modeling software to cm units - make sure your exporter (.FBX) is set to centimeters also)
- Officer model height for Takedown is 183cm (fully upright) which has been confirmed to equate to 177cm in the walking stance and 138 crouched. Also WoLvErInE has worked out a 56cm width.
- For door dimensions WoLvErInE suggests 245H x 144W. Where as Markn (Serellan) gave us a door portal measurement of 256H x 160W without the door or frame. This would suggest a door frame of 11cm thickness at the top and 8cm thickness for the two side jambs. You could use 8cm all around which would aid with snapping to the grid in UDK.
If you have any more information to add, please do so.