Now that we are back on track.....let me add a few things that pile on to what Cecil was talking about. Distance....as a generally bigger person (even at lower weights, I have "retard strong" leg strength), I tried to get locked up, especially with smaller opponents (always seemed to be drunk 140 pound dudes wanted to kick the big cops ass). Also, unlike dojo and "training environments" when an opponent with 50-100 pounds on you drives you into concrete, asphalt, walls, coffee tables and television sets (just using my favorites) where you are the cushion to break their fall......it will not be like hitting a mat. I knocked a lot of folks out on full drive takedowns onto asphalt. That is how big guys use weapons....the world is a weapon with mass enhanced velocity.
Also, exactly what Cecil said about Beltline height is critical.....now most folks my size don't get this....except I have insanely short legs for my height (less than 30" inseam"). I am really a tall dwarf. My BJJ instructors always loved working the challenge of my build as my triangle was so low to the ground, yet I had a 6 foot 5 inch upper body length. I would use my low Beltline often to get under folks with my hips.
Just trying to add some help for those look for how to counter larger folks. I had to employ a bunch of this at times myself in dealing with huge folks. Weirdly, it wasn't often, as it seems when the folks who played "the line" in football meet on the street with no pads and helmets, they understand that everyone is getting hurt and my fights with much bigger folks tended to be when they were impaired.