I was a play tester for TMWWBK and have put on several convention games with it as well as playing regularly at my club, almost all games being NW Frontier.
We do the following with our Pathans:
1. No cavalry. In the hills, the tribes didn't use them. On the Afghan plains, absolutely, but our games are all set in the 1897 Pathan rebellion, so no cavalry.
2. Most Pathan riflemen (Irregular Foot) are downgraded to 'poor shots' (hit on a 6) to represent the lower rate of fire of tribal warriors compared to Anglo-Indian troops. To represent their uncanny sniping ability, we make them some of them 'Snipers' where the enemy leader is killed on any double, not just double 1! We also have at least one unit that isn't downgraded. We field a mix of 'obsolete rifle' and 'musket' warriors in our forces to represent the mix of weaponry. (All our Anglo Indians get 'modern rifle' and British units get 'sharpshooter' to represent the greater rate of fire of the Lee Metford magazine rifle).
3. We field all our Irregular Foot as having 'Born to the Hills' meaning that they can run about over rough terrain as they like AND we give them 'Fieldcraft' so they can go to ground.
4. We field some units of Tribal Foot as swordsmen, which even in 1897 is right. All swordsmen gain the Fanatics rule, so have no short range shooting (most Pathan swordsmen had no short range missile weapon) but become Fierce so hit on 4+ in melee. At least one unit per 24pt force is upgraded to be Ghazi fanatics.They gain 'Veteran' and have 'move' and 'attack' as free actions. This makes them very interesting to play with!
5. No artillery. Most Pathan tribes didn't use any. Again, on the Afghan plains in earlier wars, this may differ.
Our typical convention Pathan force is:
1 x Sharpshooters (obs. rifle, snipers)
3 x Riflemen (obs. rifle downgraded shooting)
1 x Jezzails (musket downgraded shooting)
2 x Swordsmen
2 x Ghazi Fanatics
We can always upgrade more units to 'snipers' if the situation warrants it.
The Anglo-Indian force opposing it:
1 x British infantry ('sharpshooter')
1 x Sikh infantry (Fierce)
1 x Guides infantry
1 x Gurkha infantry
1 x Maxim gun
1 x mountain artillery (we usually give the unit 'the gentleman has a bottle' trait to reduce its effectiveness, especially if the Maxim is also being fielded)
1 x Bengal Lancers
We find that all of these tweaks give us a very 'theatre-specific' feel to the games and everyone who has played our convention games or club-night games has loved them. We play multi-player with 50+ points per side usually too (although we don't really count points, to be honest. We just try to play well-designed scenarios of our own making! We're on about 50-50 victories too, suggesting balance in the scenarios!
Feel free to borrow any of those ideas or not as the mood takes you.

Oh, by the way - almost all my Pathans are Old Glory. They are cheap as chips and paint up really well!