I am the least accomplished musical notation fellow here but it occurs to me that the only way to really get your time signitures right is to brutishly accept an outside beat, say a metronome.
Set the metronome to something that seems right start it running and see how the song works with the tempo. Somewhere you have to find an objective time source if you expect others to use it. A metronome will allow you to even watch the little hand and record full or partial beat.
I think this is very hard for 'natural' writers to do because it involves making yourself (and your creation) responsible to the rest of the world at least as far as description.
Bo