Author of fastmos, which is an addition to Linda.
Our atmos is a few years behind the other code bases, in both features and performance. The throwing mechanic makes it appear faster, but the reality is, its super expensive to do tile by tile calculations, which means that to make it spread faster, we would have to increase the rate at which it calculates all active tiles.
So essentially, short of porting Bay or TGs system, this is about as good as we will be able to get.
Considering that byond is single threaded, this is extremely unlikely to change in the future. Its a known limitation of our atmospherics system. Anything short of a port of a more modern system will not change this dynamic.
As far as the 24 minute thing goes, before fastmos, our atmospherics system was 4 times slower.
So um, that would be 100 minutes.