" Incidentally has anyone any thought on how powerful a chemical or dei
laser you could fit into a standard sized missile >at various tech levels?"
You mean as a cheaper recoverable missile? The toxic results from a
chemical laser would suit a device where you just unscrew the warhead and
salvage the missile body ... why bother decontaminating and refueling the
warhead when you can salvage the body of the missile.
Or possibly as a cheap type of laser mine? No need to worry about
radioactive material entering your atmosphere from a damaged planetary
defence grid.