I believe the starting rough guideline that's been more accepted here is the "one inch of fish body (for relatively small-bodied trops) per 1 US gallon of tank volume." For you, with a tank volume of roughly 33 US gallons, that would be at most about 33 inches of fish which works out to roughly about 83 cm of fish body I believe.
Now there are all sorts of tanks that experienced fishkeepers can make work. There are people that like planted tanks with a single small shoal of tetras, way understocked. There are people that will go to great lengths and expense to overfilter and overstock to have tanks teeming with fish everywhere you look. So part of it is style and part of it is effort level (obviously, lots of fish means lots more filtration, filtration maintenance and tank cleaning!) And one thing to be aware of is that there are probably those who, in their excitement about all the beautiful tropicals out there, tend to want some of each, which is very understandable. But perhaps some of those will look at there tank later and realize that the crowded look wasn't quite what they ultimately had in mind and wish they had gone for something more peaceful, you never know.
There's also an element of risk. A tank overstocked beyond the rough guideline level is also a much bigger emergency if you lose electricity for any length of time as its quite dependent on its systems running full tilt I believe. And then there's a factor that's hard to define very specifically I think that when you are a just getting started in your first few years of fishkeeping, the kinds of challanges a tank full of fish can present can be a surprise and an overstocked tank makes those surprises much, much more difficult to react to I believe. So there is a definate benefit, I would argue, to making the more difficult decision to not overstock the tank when you are still finding out all the aspects of the hobby. A forum like TFF naturally attracts people who have been keeping fish all their lives and many of these have correct reactions to emergencies that for them are quite "second nature", or easy, but wouldn't be without all those years of experience.
I don't know quite where you feel you fall in that scenerio, but just throwing it out for you to think about. Good luck. I'm not great with the detailed personalities of the Barbs you want to discuss, so I'll leave that to others. Certainly any type cory and the cherry barbs get along with most anything else socially I believe.
~~waterdrop~~
