I need to intercept quotes and have them use the default shipping methods and not use the shipping methods defined on a website level.
Is this doable? I've dug through the code for hours and can't find anything useful.
You need to look at Shipping/Model/Shipping.php and the collectRates call. The code would need to be changed to not look at store level when getting list of carriers
Its a big task potentially as its still going to look at all the config options at a store level.