String the glass up again, with the start/finish point for the string in the middle of the longest section of the seal, ie the bottom edge. get someone to put moderate pressure on the outside of the glass, both hands, with spread fingers.. to evenly distribute even pressure over the seal against the window aperture... with this pressure maintained, pull one part of the string till it reaches the first corner, then stop, and slap the glass with a flat hand in the area that has just been pulled, this will seat the rubber... then continue with the other end of the string in the opposite direction, till you reach the adjacent corner, once again, seat the seal by slapping the glass... even pressure should be maintained at all times, continue in sections till all the way round. Once the pulling in has been completed, it will probably necessary to seat all of the window once again, just by slapping the glass, check for uniform fit on the inside of the glass, and may need a little fiddling where the rubber seal fits over the inner rear 1/4 trim... use a blunt wide blade screwdriver for this.
When pulling the string out, don't pull it towards you! this could tear the rubber seal... Instead, wrap the string round your hand and with you knuckles touching the glass, pull the string like you're pulling it to the adjacent side of the seal..
Easy really...
Thom