thanks, that put me on the write track. turns out i was getting rw the whole time, but i didnt have write permissions. did chmod 777 /system and it worked, and when i was done i put it back to chmod 755 /system
if anyone has a similar problem, the command 'mount | grep /system' is a great way to check to see if you actually have it mount as rw or not.
before this i tried a couple of the remount apps, as well as the mount as 'rw' option in es file explorer and they always fail to mount, presumably they aren't failing to mount but are running into the same permission issue and can't write