Thanks for clarifying your goals, that definitely changes things.
You’ll need to film a set where you’re exerting yourself more to get a good idea of how to address your form, and I would ‘reset’ every rep, not the touch and go type of reps you’re doing here. I would do a difficult set of 5. Doesn’t have to be a true 5 rep max, but the weight should not be easy to lift by the 5th rep. I don’t believe you’re in danger of hurting yourself by doing this with the form you’ve demonstrated in this video.
Mark’s advice on finding a 1RM is probably good. I don’t do any calculations or tests, but I’ve been lifting long enough that I can do most things just by feel. I don’t really run a set program at all, I just have a few lifts that I consistently do within particular rep ranges. I talk about my style of training in my log, if you have an interest, but I don’t really recommend doing what I do, lol.
I’ll give you a basic layout though. I alternate how heavy I go on my main lifts weekly. One week I’ll work up to a heavy single or double, the next week I’ll work up to a heavy set of 5-10. Then, after I’ve done my heaviest set, I’ll back off the weight and do more work for volume. It could be 5 sets of 10, could be 3 sets of 10, could be 6 sets of 6. I just try to mix it up. The weight I pick is anywhere from 50 percent of my max to 70 percent. If I pick a weight that’s just too heavy on my first set (this happens sometimes), then I’ll lower it for subsequent sets.
So for instance, on Monday I worked up to a 445 squat for 5 reps. I picked 6x6 for my volume work following that, and used 315 for the weight. I’m capable of doing more reps at that weight, but for volume work, you don’t have to work to your maximum capacity every time. I’m also likely to do more reps (more like 5x10) on my volume sets if I’ve only worked up to a single for my heavy set. In this case, the 5 reps took a lot out of me, so I was happy to keep the overall volume lower.