That video above shows Rolex hands which are made of solid white gold and responds well to polishing. Most hands on the other hand (pun not intended) are plated brass which do not as the plating can easily be worn through. Use of rotary tool not recommended.
Well I think I've successfully done it. Thanks for all your words of advice. My method was to first assemble the train wheels and bridge and check they were freely spinning - all good. Then I tried the barrel held by its bridge without adjusting the tooth and as expected, the spin came to a hard stop and lightly bounced back. The gap of the good teeth is around 0.4. My 0.5 screwdriver blade got over half way between the gap of the bad tooth so using this I did a straight firm push (no back and forth levering as I hoped the wedge of the blade would push apart). On pushing the 0.5 home, I moved onto the 0.6 and repeated. Then onto the 0.8 (sweating by now as it seemed to take more pressure to drive home). At this point, I tried it against the train, and again, the same happened with the bounce back. Feeling my luck was going to run out soon, I applied a tiny drop of HP 1300 oil on both sides of the 1.00 screwdriver blade in the vain hope it may ease the blade in, and it did seem to ease the push home. On examining, I recalled @AlexeiJ1's advice that it doesn't have to be perfectly straight, just more inline, and it did appear improved so trying with the train again, it spun freely with no resistance past the imperfect teeth. Of course I won't know if the performance will be affected until she's up and running but for now, I'm pleased with the result. I've attached a photo of the straightened tooth.