It will form a salt, thats not the problem. The issue with different salt forms is that some of them will be hygroscopic, meaning they will absorb water from the air, becoming goo/oil instead of solid.
The only solid salt forms for DMT I've seen describe in literature or saw home tests is DMT fumarate or picrate (but dont mess with picric acid!) . That being said, I've never heard of any tests with DMT tartrate, it might be its solid, it might be its oily.
If you're willing to "take one for the team", Im sure others like me would be interested in hearing the results. You can always recover your DMT by freebasing and pulling with a solvent again if it doesnt end up like you want it.