By yellow sealer do you mean a primer/sealer? I would not mind brightening it up a tad as the sample I have had mixed up is not quite as "bright" as I hoped.
Our local auto paint supplier mixed it up off the computer, there was no problem finding the code. I see Cat has given you the mix so hope you are good to go.
I hope to be ordering a quart to do the cutting in this week...should I just go ahead and get what I need for the whole car or is there a shelf life? Likely won't have the car painted for a few months at least.