20,000 lb of cargo...
After investigation this would be reduced to 16,000 at 15,000 feet and more like 10,000 at 20,000 ft. (highest possible altitude w/o pressurization.)

After discussion it was decided that given this and the size of the gondola/cabin, it was more reasonable that the hull interior could only accomodate perhaps 10,000, with any extra being carried outboard like a helo would move a howitzer.

6 party members 1800
NPC Pilot
2 NPC Sailors
4 NPC ballista gunners...2100
(human weight 3900)
2 light ballista+ammo 1200


7*13 man-days of water...760
50*13 man-days of food...1300
(provision weight 2060)

...total so far 7160

2 extra gasbags 300
wood for hull repairs 300
4 replacement props 100
Extra rigging 200

...repair supplies 900
total 8060

1 man-day's provisions:
8 lb water
2 lb food and consumables.