David (vZakat), I haven't had a chance to look at that video until today because this thing doesn't have flash on it.
I just watched it once (like 6 hours ago too) but here's some things i remember.
the biggest thing i noticed is chad continually jumped out of your first hit of overb. you could rely on him to do it, then steal his second jump with a well placed uair or nair. Eventually leading to a fsmash or a platform techchase.
Another thing you could do with this is grab him uthrow him and chase his DI, waiting for his second jump (odds are he would have), then combo till you get sick and fsmash. (I do this with peach)
after your dtilts you tried to SHfair then FHnair. you got it once, but every other time he jumped away from you. I am of the opinion fair should be used when roy is close to the ground, whereas nair is for rising attacks. basically, fair should be used on the way down after a SH whereas nair you can generally shuffle. fair just doesn't have enough stun time otherwise. Nair onto platforms, fair coming down off of them. (IMO)
good recoveries for the most part. Make sure you hit your sweetspots, ganon's uair shouldn't be beating the blazer.
you walked to the edge, then dash cancelled and started charging the flareblade. if you're walking you don't need to dash cancel.
when i spike people into the ground with the overb, i try to outspace the get up with a dtilt (you can get a tipper at least) however i typically mess up, whereas you DDed around and got a grab. i think the dtilt would have more payoff but well done anyways.
you're pretty much to the point where asking for general advice isn't going to get you very far (because you're not very predictable... at least from what this video shows and what i remember). At this point, it's just a matter of playing around with your style and trying to vary it against different opponents and seeing what works. pay attention to their habits (always easier to do in retrospect) and try to learn how to punish everything.
Very well done.
I might try Roy on Chaddd next time i play him in tourney if Peach fails me.