in our website www.theprinterdepo.com we are going to implement google checkout. However I am not sure in what shipping methods or strategy to use.
In this page: https://developers.google.com/checkout/developer/Google_Checkout_XML_API_Carrier_Calculated_Shipping#Process
Google says that they calculate based on the total weight of the items, but the thing is if one person buys one printer thats fine, but if he orders 3 printers of 50lbs, the shipping cost is invalid calculating it with 150lbs. It has to be calculated as 3 packages of 50lbs.
How would you do it in this scenario??
The "limitation" mentioned above is only if you will rely on Google to calculate shipping for you using what they call carrier-calculated-shipping.
You do have other options to calculate shipping:
you can pre-calculate using whatever formula (or shipping service/plugin) you have based on the cart contents (you would know this prior to handing off the cart to Google for Checkout), which is essentially sending a flat rate shipping cost to Google, or perhaps;
use the merchant-calculations-api option so you can account for the destination/delivery address (not just cart contents). This option is more complex (you need to handle callbacks from Google), but it does give you critical information to work with when calculating shipping.
hth....