The thinking behind the battery thing is to trick the truck into thinking that it needs to adjust the air/fuel mix. After reconnecting the battery drive the truck like you stole it. I don't know if this works because the X adjusts the idle, A/F mix, etc. on it's own.
As far as closing the res/ I left mine in place, covered the opening with electric tape and sealed it back up. I checked it this past weekend and it has been holding quite well for the past year.