One problem I have with this idea is that the cooling profile from releasing sulphates into the atmosphere looks very different from the greenhouse gas warming profile. For example, the latter has a more pronounced effect at higher latitudes, since GHG are insulators. The arctic is getting hit harder than the tropics. The former, I would expect, would affect the places in the world that get the most sun, since it is effectively a solar filter. So, the lower latitudes, in other words.

If we have a baseline scenario A of what would have happened without the GHGs and B with what is currently happening, this would make for a scenario C that is neither of the others. I would submit that C would likely be as far from A as B is. Yes, you might get global warming under control in an accountant-looking-at-only-the-bottom-line sort of way, but this would still represent a massive climate change into uncharted territory. Would scenario C still be preferable to B is the question I guess?