Well I for one do trust the sales hype for Morgan fuels. Well, at least it's always done well by me!! I use nothing but Cool Power fuel and I don't use any after run oil at all. I've had engines that have sat idle for more than a year with no special treatment and they have zero rust in them. So my opinion is you are going to be just fine without the after-run oil. Especially if you are only going a week between runs.

Ken