THE FOLLOWING IS A HACK
not cannon AW rules.
If for whatever reason you dislike how gangs / battle are rather arbitrarily decided:
I've found it helpful to rescript all gang harm/armor as number of people and the odds.
3:1 in this case would be... if you've got three times their number.
whereas 1:3 would be... if they've got three times your number.
average the results as it works for your group, or decide if a gang is half way, if they should be more
one way or other based on the circumstances, then disclaim why so the players aren't taken by surprise.
They shouldn't stand a chance, get +2 harm/armor (3:1)
You've got the advantage, get +1 harm/armor (2:1)
You're evenly matched (1:1)
You're disadvantaged in this fight, they get +1 harm/armor (1:2)
You're seriously outnumbered/out-maneuvered, they get +2 harm/armor (1:3)
You're not coming back from this one, they get +3 harm/armor (1:4+)
Now every combatant matters, you can decide by how much on the spot or ahead of time, whatever works. If people die, then the force afterwards is weaker, or weaker until the wounded get help etc. This was helpful to me and my group because it allowed us to quickly evaluate more complicated fights. Like being able to lure you enemy into a trap (your people have more of an advantage, maybe it off-sets a numbers or just betters you by one step). In general you should not dynamically change the odds after a fight begins, (unless everyone is down with that), best to decide after when you declare the dead and wounded. I made up group harm rolls that can be made after a fight depending on the harm suffered to help determine actual dead/wounded counts, but really... we never needed to use them. Abouts as per the narrative were all that mattered.
As for Gunlugger, we handled NOT TO BE FUCKED WITH, as the gunlugger counts as 10 guys whenever he didnt have the advantage over his enemies, up to gaining the advantage. This fits well with the original wording of the move, where the word Battle just means: a fight has broken out and everyone is engaged. (i.e. doesn't fire when you jump a gang in an alley, not until after the first exchange and they're fighting too) 1v1 the npc has got 2 or 3 harm worth of life. 5 npcs have a clock with 6 harm worth of life, but no number difference for harm / armor.
flexible examples:
10 guys vs 13 guys is pretty even.
3 guys vs 9 guys are seriously numbered
50 guys vs 30 guys have the advantage.
and
the gunlugger vs 1-5 guys has the advantage
the gunlugger vs 6-15 guys is evenly matched
the gunlugger vs 16-26 guys is at a disadvantage
the gunlugger vs 36 or more might be trouble
this logic also holds true for adding the gunlugger to some guys
G and 5 guys count like 15, so they could take on like 10 to 20 and still be evenly matched (pretty good for 6 dudes vs 20)
Anyway, figured I'd toss something out there in case you and your group (or anyone else reading) wanted to have something a bit more flexible. You can cap the gunluggers bonus at evenly matched too if you want to make those single baddies really count. We called this secondary stat: BAD. Then we said enemies could be given increased bad as a special move. Let players increase their bad (including the Gunlugger) with advance move for +2 or 3. You can set the BAD granted by not to be fucked with to anything you want. You can attribute BOSSES to have like 5 BAD, and therefore needs 3 normal people to off-set their advantage. You can give the seriously scary / violent / drugged NPCs 2 BAD, doubling their effective gang size. (starting player gangs have a total BAD equal to the AW declared number of gang members) You can even increase BAD when someone is seriously high on some violent drugs.
Whatever works.