Setting a fixed shipping rate and a combined variable shipping rate

[tonehome]

Hello, I've been wanting to charge a flat rate of $4 regardless of number of items or weight. I want this to apply to media mail items only. Also, I would like to combine shipping by weight to items mailed by any other method. Most likely this will be limited to USPS Ground Advantage. I've tried using shipping policies under business practices to no effect. I'm not positive I am doing it right.

If I do get it to work, I would like to know what happens if a buyer mixes the two shipping methods in one cart.

Any assistance would be greatly appreciated.

[tonehome]

I accidentally figured this out when I had to change shipping methods on one of my categories. Was a bit of a pain to have to bulk edit over a hundred items. Thank goodness I don't have thousands.

I normally check to see if changes work in Private Mode. Worked great on promotional items. I assume it worked on the USPS Ground Advantage. It won't let me attempt a guest checkout when one of these items is in the cart. The mixed order seems to work as well. 

Sorry if you wasted any time on this.