It might be dependant on the plotter driver you use, but for the DWG to PDF select 'properties' from the plot dialogue and then 'Custom paper size' and 'Add' that starts a Wizard which lets you add your own paper size.
My 1st suggestion just me I write all my custom .mnu in notepad and use menuload which makes a cuix. You can copy and paste between CUI editor and notepad so steal any commands and toolbar icons etc. This way your menu's are seperate from the main menu.
^c^c(ssget)(command "copybase" "0,0,0" "p" "" "_ERASE" "p" "" "_pasteblock" "0,0,0")