"The earlier had he changed it..." The inverted word order, "had he", serves to emphasize that you are using past subjunctive mood, thereby making your meaning clear.

If he had changed it earlier, the result would have been better: this sounds more natural and is a 3rd conditional (you imagine a change in a past situation and the different result of that change).

The first sentence, “The earlier he had changed it, the better the result would have been,” is the correct and natural option. Yes, it is a conditional sentence, specifically a third conditional structure. Here's a detailed breakdown of the sentences: 1. “The earlier he had changed it, the better the result would have been.” * Explanation: This is a correct third conditional sentence, used to talk about a hypothetical past situation and its consequence. The structure is: * If + past perfect (he had changed) → would have + past participle (would have been). * Meaning: If he had changed it earlier (in the past), the result (also in the past) would have been better.