I question what "it worked way better than I was hoping" means in this context. If you're saying that filtering the input data to create a uniform distribution

I question what "it worked way better than I was hoping" means in this context. If you're saying that filtering the input data to create a uniform distribution created a uniform distribution in the output, I'm not sure why you'd hope for any less--that's exactly what I'd expect to happen. But that's a poor measure of success, because you don't know what side effects that had: the removed data ostensibly contained other variables besides your binary variable, and you don't know if those variables were sampled in any useful way, so I'd be hesitant to say this worked well without at least an attempt to measure those other variables.