[New spell] Sustenance of the Spider

Awesome. Exactly.

{Citation please}

On the contrary, this makes Circle behaves like Room. Your interpretation is in direct opposition of the corebook itself.
Incantation of Putrid Wine, ArM5 p 122 "... and they remain malodorous even if removed from the room."

I spent good money on it (to use your own phrase).
I consider it a very interesting concept. I happily mine it for ideas.
I advice everyone to check the level calculations before they use spells or effects from it.
That is all.