Regarding Choi, I mentioned in my b/d earlier about his foot work and ability to avoid take downs, something jb mentioned earlier, but he does love to counter strike and is mainly a stand up fighter.
Its not to say he has no grappling, he trains wrestling and conditioning in his training camp often and even started jiu jitsu at a school 8 years ago when one became available close to him.
I like tavares but think his best chance of a win here is when he is fresh and in r1 with a sub otherwise reckon Choi will have the much faster and more accurate hands and will buckle tavares, this is certainly chois biggest fight to date but still ultimately favour choi, may take a flyer on choi r2/r3 finish even.