"Oddly enough though, on the B757 and B767 aircraft, moving Rudder Trim moves the Tiller a lot more noticeably."
This is probably simply a matter of Rudder Trim authority, B73567AMT. Some 767 rudder trim systems can move the rudder up to 80% of full rudder travel, whereas on the 737NG, for example, rudder trim is limited to around 62%.
Rgds.
NSEU.