If you have a rug on the kitchen floor I'd just take it up while he is being housetrained. Once they wee on something, they will keep going there because of the scent and you need to use something like Nature's Miracle to destroy it enzymatically (regular soap won;t work). I threw out a few area rugs after housetraining Jaspar and in future won;t keep them donw at all when they are young. One of the problems with wee wee pads is sometimes it gets them thinking any pad is OK; also they plain old like soft things like carpet or rugs to pee on (as do kittens) so it is better not to even give them the option if you can take it up.
Note Bruce was saying 1/2 cup for his adult cavaliers -- adults usually eat less than puppies. Again feeding amounts really depend on the size and metabolism and amount of exercise for a given dog.
Try not to get overly worried about him too -- dogs can sense your anxiety and they in turn can become anxious simply because of this, so do your best to relax and feel positive about sorting out his tummy problems.