[talanum1 (OP)]

There is a very obvious difference.
Like charges repel.

There is a sign difference in the force laws but we can arrange -GMm = kQ(-q).

[talanum1 (OP)]

My model predicts antimatter will have attractive gravity with matter.

It also gives a framework for introducing negative mass: the negative mass is just encoded with left-out points of space.

[Bored chemist]

My model predicts antimatter will have attractive gravity with matter.

So does everyone else's model...
Were you expecting a medal?