I don't use wterm, but most terminals have a --geometry option like with Eterm I think i did Eterm -g x y h w x, 7 being where the top left of the window goes, and hw being hight and width obviously, these numberes are based off your resolution in xorg.conf so you could try something like exec wterm -g 100 100 400 400 and play with the numbers. You can do many cool things with the syntax of terms, you can have it auto run programs like top, or pine to check your mail.