A few more thing to consider:
When you cut the power down when landing, the ac will glide like sack of spuds (slight exageration). Use the descent to circuit height to get a feel for this. Also consider landing distances.
...and taking off is the opposite. Long run, low rate of climb.
Depending on your airfield & size of friends, 4 up in a warrior is possibe (skinny ones to the rear please!) but you will probably need the fuel on tabs or below. Like others have said - Check W&B.
BtB