no, while "ככה" and "כזה" have similar meanings, we use them differently. and "ככה" is not correct here. as mentioned earlier, using "כזה" in front of an adjective is like a slang way to accentuate that adjective.
Yeah but Americans will put in the like (Not in a "CLUELESS" movie way but colloquially) if it's a comparison between something of a similar size. So you're saying that this is just commenting the dog is big vs the dog is (as big as)?