If you'd like, we can go with the smaller dinos. Some were the size of chickens (~5 kg); many were smaller. The big guys (T. Rex @~6 tonnes, Triceratops @~5 tonnes, the sauropods @ 20-150 tonnes) always get the top billing because they are so impressive. Most of these critters, however, were less than 100 kgs in size.
Let's take it a step further. The largest land mammal that ever existed was the Indricotherium at about 20 tonnes -- or the size of four African elephants. That's the size of the smaller sauropods, and larger than just about every other dinosaur that existed, and yet it wasn't "buoyancy sorted" with them, but with later mammals. We could go on with mammals such as the megatherium (7 tonnes), the titanothere (6 tonnes), the Columbian Mammoth (7 tonnes) -- all comparable to dinosaurs in size, but never found mixed with the latters' bones.
Oh, and then we have the lovely terror birds that cropped up shortly after the demise of the dinosaurs, with some species actually hanging on until a couple of million years ago. These flightless birds ranged up to 4-meters in height and between 50 and 300 kgs (birds are built a bit lighter) -- and yet they are not found mixed with dinos or with more recent remains, regardless of size.
And, let's not even get started on the fish, aquatic reptiles (they weren't dinosaurs) or aquatic mammals, that magically sort themselves out in the fossil record in a manner reminiscent of vast scales of time and not "buoyancy sorting."
Methinks you are not really researching any of your arguments and are simply parroting what someone wrote on a creationist web page. Next time you do a web search, ditch the creationist sites. They are notoriously light on science. Go for things with .edu extensions. It's there that you will find most of the actual research being done in any given field (creationist "researchers" typically skim these sites for the odd out-of-context quote they can mine to bolster their untenable positions. Eliminate the middleman and go there yourself). I also find the science and nature sections of any good bookstore to be a wealth of information, expecially for a megafauna fanatic such as myself.
Right. This is where I dismiss what you've said out of hand. I'm sure you expected it. Bouyancy far and away better solves the issue of how animals appear in strata and the extremely good sort of said strata all things considered. I don't tend to dismiss things that tend to tell the story better - especially when the theory explains more than it causes need to theorize about. Sorry, the fewer elements needing explained by a theory, the more likely the theory is to hold up. How many theories and subtheories is evolution up to now?..