The boom 20 and 50 are all good, but what if you went to the properties button and you could resize the bombs. So you could make it a boom 10 or a boom 75 and once it got to a sertain number it whould turn into a nuclear explosive. The larger the bomb got the larger the explosion and larger the blast radius. Once it got to nuclear level it could make a shockwave around an island. But every time you made the bomb bigger, you sacrifice some mass.
Ps- I know you can make xml bombs explosions bigger but it also makes the bombs huge.