I'm truly in over my head with this google checkout thing.

zencart 1.3.8a
google checkout 1.4.7

I have an acct, I have sandbox, I even managed through the infamous tax rates issue. Now I'm on to the calculated shipping mess. The code has been added, and the shipping generator run (which is where I begin to experience problems)

The products I sell usually are sent USPS first class mail (under 13 oz, etc), and calculated by the USPS module by weight - so exact shipping. My first question is, because I have prowled this thread and there is some confusion on this matter, does google checkout handle USPS first class?

Second, can google checkout calculate a custom shipping cost for each package, based on weight, like the USPS module does? In addition to my main website, I list products on ecrater, which uses google checkout but you have to manually list the shipping cost per item; is that how google checkout functions in general or is that something specific to ecrater?

I've had 'google calculated shipping' on both true and false. I've altered the 'carrier calculated shipping configuration' numbers multiple times. I've also played with the 'default values for real time shipping rates'. Either I've just not hit on the right combo or I'm truly missing something.

I guess the main question is more about google checkout's shipping calculation capabilities, and if it can, how I can make that happen, becuase I'm failing miserably.

Thanks everyone.