I think the model of time and space in Primer is more consistent because it's a very specific kind of time machine.
If I recall correctly, you'd turn on the machine, wait N hours, go inside the machine, and in the next N hours you'd be going back in time and come out the other end at the moment the machine was turned on. So you would have spent 2*N extra hours, the machine would have always been in the same spot, so there'd be no problem with traveling through space.
There are still problems with the paradoxes, but that's part of the plot of the movie.
If I recall correctly, you'd turn on the machine, wait N hours, go inside the machine, and in the next N hours you'd be going back in time and come out the other end at the moment the machine was turned on. So you would have spent 2*N extra hours, the machine would have always been in the same spot, so there'd be no problem with traveling through space.
There are still problems with the paradoxes, but that's part of the plot of the movie.