This is not enough to think like this. When two nucleii come together, fusion is just one possible outcome, and not very possible at that. There are a host of other possible outcomes, mainly scattering and non-elastic collisions (e.g. O-P for high deuteron energy). Fusion is never, ever an outcome where 'the majority of particles' get to fuse. Start doing some reading, and some maths. This is no good. Your are not making any progress with your understanding of fusion.
You did not read the description.
Particle scattered at a small angle will return to the axis magnetically. And this will be repeated and repeated before fusion event occure.
Non-elastic collisions will have near-zero probability at energies at which fusion cross section is maximum or close to maximum.
O-P for the reactions of interest we can exclude at all.