I have to deal with the transoprt of various fosters and upcoming, I have a shy cat flying from FL to NY.
I want to sedate her because she becomes rigidly frightened. Another foster I know, says:

Be sure to give them the sedation while they are not aggitated, because if you give it to them while aggitated, they can bacome more aggiagated, having the opposite effect that it is supposed to have.

The pill I would use is called Ace (acepramizine)sp?

Also, I would put a Feliway diffuser in the room you choose to keep Cubby. Then only let him into one room at a time, until he sees the whole house.