@Thermo:
So do the knowledge skill, perception, and assensing rolls. For the spells, usually people don't mess too much with the strange and obscure methods occultists use once they've hired them. The foci won't bring too much attention either, especially with all the mana flying everywhere. Cast the spells and take the drain. Whatever drain you suffer carries over, so you can recast if you don't get what you want but you have to live with the drain.
Your spirit can access whatever place you're at regardless of wards.