You're very strong, so I'm going to be splitting hairs a bit here, but I think it's worth nothing, since you did say you are interested in powerlifting.
You benched 405 for 0 reps in that video. Your first rep was touch and go, not paused, and your ass came way off the bench. And you had help on the second rep. It's hard to tell from the video if you're actually strong enough to hit a real 405 bench press under competition conditions, but you're at least close enough to indicate that you've got some real potential. If I were you, I'd consider doing a drug tested meet now, because you'd be super competitive in one of those. Get some numbers in the books as a natural athlete, because that's something you can never go back to. Just a thought.
As to what you should do going forward as far as steroids go, I would give you the same advice I would give anyone. A test-only cycle, for 10-12 weeks, at 500-750mg per week. It would look like this:
weeks 1-12: Test E or Test C, injected twice weekly, for a total of 500-750mg/week
Anastrozole(Arimidex): taken every other day, at .25mg. Adjust dose if necessary if either high estrogen symptoms appear, or if bloodwork indicates high estrogen.
weeks 14-19: nolvadex (tamoxifen citrate) everyday, at 20mg/day. This is your pct.
optional: dbol at 25mg/day for the first 4 weeks. I did this, and really liked it. It's fast acting, and great for strength.