(wait where is attack number two coming from(shifting?)...he charged in the first round which I have already taken into account, which means for round two he could do what he just did, provided he makes his DC 14 save not to be stunned by the center eye)
RA, I treated this first round as a surprise round, I would normally allow you to move up like you did but, there is a chance that you would have tipped the beholder off and denied Stulgar the benefit of surprise to start off the battle, despite the fact that, his charging tipped off the Gauth any way and that it has all-around vision and knew you were coming thanks to Stulgar and was simply waiting. However, I will allow that as stulgar charged you could probably get a moved action to get within only one range increment instead of two,thus causing you to hit for 16 damage, I had assumed that since all three of you (seat,lily, and yourself0 had readied actions and thus they all went off at once, i.e your attack occurred before the web took effect. However, the action point more than makes up for it and the point is now moot.)
The gauth will have another turn before your actions happen assuming none of you can beat 24 on initiative. But I am almost certain with all of the dex in this place that its possible for one of you to go first.