Dakkaron

@openend If you are looking at maximum power, would it be maybe better to go the same route as real-life weapons engineering does and not increase speed but instead use some kind of explosive payload? This is done in the real world because that way you can generate the kinetic energy used to destroy the target at the target, instead of at the gun. That is much more efficient and easier, since increasing the energy at the target by increasing the speed of the projectile has quite stongly diminishing returns.

@openend Just to understand your question better, what is your goal with that speed? Do you want a weapon that is so fast that it cannot be dodged? Then something laser-based might be the fastest you can get. Or do you want the most kinetic energy possible to destroy the target?

@MontyWild: using binary and two hands you can count to 1023, not only 511.

@Mindwin: the mass is very important for the ecological impact, since it has to hover somehow. If it is hovering by being as light as air, there is no impact, but if it is hovering by pushing air down to keep it's altitude (similar to a helicopter) than this would have a massive effect since it would blow a lot of water away.

It seems to me that this answer does not actually attempt to answer the question. The question was "Do 4-state symbols represent twice the information of a 2-state symbol?". The answer only talks about the difficulties of storing or transmitting more states per symbol. The answer by @hyde seems to be much more fitting.