greensRus

Im new to this GPS but I just finished reading online that the 'Map Datum' shouldnt be set up as NAD27...but mine is. It also said that it should be set as WGS82 or something like that... but I dont have that in the drop-down menu? I do have WGS72 though... would that be the same thing? BTW, I found this in [Tools-Settings-Navigation-Map Datum] Someone please help me out.. does it really matter?