The AT-AT is based on an 80mm x 80mm base and can move:
Forward 1 (Green)
L/R Bank 1 (White) two consecutive white moves equals a stress token (red move) and
Agitlity-0 (The Falcon has an agility of 1 and there is now way the walker is as agile).
Hull-9 (This was play tested to determine a balanced and idealistic level of protection)
Veers has the option of remaining stationary in order to roll an additional attack die. This is can be a useful option however you are slowing your advance to the target.
Ties and the walker can deplete the target shields however the hull value can only be affected by the AT-ATs heavy lasers with a Target Lock.
'Right of way' The AT-AT does not take a damage card when an overlap occurs.
AT-ATs hull is only damaged from crits and each crit is a face down damage card. Due to its heavy protection normal hits are ignored. This may sound extreme however with the walker having no agility you will find the hull will eventually be breached, depending on the effectiveness of the Tie escorts and accuracy of the Rebels.
The scenario ground target should be
We playtested this scenario a few times on a 3'x4' board with 100 points a side with no upgrades.
Rebels- Luke Skywalker, Biggs Darklighter, Red Squadron Pilot and Rookie Pilot. (97)
Empire- AT-AT, 2x Black Squadron Pilot, 2x Academy Pilot (100)
Without going too far into gameplay, we found that the walker could not get into range until turn 7. This gave the Rebels time to hit the AT-AT hard or ping any Ties close by. The Ties, with the support of the walker had to fight hard and roll well, occassionally spearing off to ping some of the targets shields. We used different approaches, The Rebel player first opted to concentrate on the walker to deplete its hull vale, this proved costly as two X-wings went down from the Ties. Another approach was to hit the Tie escorts and concentrate all remaining attacks on the walker, this proved a little more successfull with 3 Ties shot down although the AT-AT was within range 2 and stationary (+1 attack) engaging the target. With 2 hull remaining on the target, a concentrated volly from 3 X-Wings bought the beast down (although we did see some miricle Crit rolling).
The Imperial player tried two options, first 3 Ties shot forward to deplete the targets shields (didn't go well). That left one Tie trying to escort the Walker which as you may guess ended badly too. That being said the walker was in range and the target was down to 1 Hull when the AT-AT came down. The other tactic was to provide close escort, concentrating on keeping the X-Wings busy, this worked well and in this game due to some good rolling and placement the target was destroyed. (Unfortunatly Biggs chose poorly with his maneuver overlaping the walker and rolled his last damage)
Many of the adjustments we're made by people on the forum and the games were very enjoyable, so thanks for your input.