Cleon
Legend
I think I can go along with that carrying capacity, though it's quite high compared to the flying carpet. I guess it stands to reason that a ship-like thing could carry more than a carpet.
Quite.
It's a flying ship, so ought to have a ship-like carrying capacity.
So shall I amend it with:
An aracheon can fly at a speed of 40 feet with poor maneuverability, or 30 feet with clumsy maneuverability if the vehicle is heavily armored or carrying a heavy load. The aracheon can also hover, as per the Hover feat, and will hover in midair if left unattended. An aracheon's normal carrying capacity is 500 lbs. per 5 ft. square it occupies; its "heavily loaded" carrying capacity is 1000 lbs. per square.
I was trying to find a magic item that does something similar to one of the spells that can be made permanent to compare XP costs, but I'm not finding one right now. But that might help.
Yes, I had a quick rummage through various sources while I was originally drafting the spell and couldn't find anything concrete. There are some guidelines for building Spelljammer type ships on spelljammer.org, but they aren't "official".
I guess it doesn't make much difference since it's a Tso-only spell, especially as only Tso who participating in the casting can fly the aracheon, 4000 XP just feels like it could be a tad low.
Still, I think it might be close enough for our purposes. We could always bump it up to 5k or 6k later if we wanted.