The answer is grappling. I hate to say it, but striking doesn't work doing it at half power. The best you can do is not hit them in the head if you want to be nice. Judo gives me a lot more options. I can take the person down without slamming them, put them in a pin till they calm down, or choke them unconscious. Furthermore I don't feel quite as pressured to keep a person out of my face at all costs. I know I can control a bigger person (within reason) in a clinch no problem, which gives me more leeway to try and defuse the situation.
Besides osoto, I'd think sasae is a good takedown for this, not too hard to do without a gi, the footwork is similar to osoto so less time investment to learn both, and gives you good control over their upper body as they fall so you can keep them from slamming their head on the floor.
Scarfhold is the bomb for controlling people, I can be held in that pin by a much smaller person even though I know how to escape it. It leaves one of their hands free behind your back though, so I think it's a bit risky, as they could draw a weapon with it. Side mount might be better as you can either control both arms or at least keep them from reaching their pockets/waistband.
P.S. That being said, I'm not a LEO or a bouncer. I've been in only two adult situations ever that wound up becoming violent (both on/around public transportation!), and anything else I base my opinions off five years of breaking up brawls between highschool kids (albeit most of them were bigger than me and probably 3 years older than they should've been at that grade level, but still), or the opinions of instructors who were cops/corrections, so my 2 cents and grain of salt please. IMO, find a Judo instructor who is a cop and work this out with them.