No problem with the In Checkout setting; I just set it to use that, and will check on it periodically to see if it helps with the stragglers.

As far as the failed CC message, I think keeping it flexible is good. We will be changing it from "email support" to "click here to visit our support center" that'll be an Ajax FAQ module of sorts. Since I'm not sure what your plans are for it, as long as there is some form of customization (a way to actively guide the customers in case of a CC authorization failure), do what you must!