In terms of physical training, Naruto would need to train his body to withstand the greater power of both Kurama halves. He could do more strenuous exercises like lifting extremely heavy weights or running at high speeds for long distances while in a Kurama - enhanced state. Also, his mental training would be crucial. He would need to be mentally strong to handle the influence of both Kurama halves on his mind and to be able to access their power when needed without losing control.
Well, having both halves of Kurama would significantly boost Naruto's power level. Kurama is already an extremely powerful tailed beast, and with the complete form, Naruto would have access to even more chakra. His attacks would be more powerful, and he could probably use some new and enhanced forms of his existing jutsu. For example, his Rasengan might become much larger and more destructive.
His training would probably be more advanced. Since they know his connection to the fourth, they might give him access to special jutsus and training methods that were reserved for the elite.
He might gain the ability to teleport short distances. Since Kurama's chakra is so powerful, it could potentially warp space around Naruto for a quick teleport. Another new ability could be a more powerful chakra shield. With both halves of Kurama, he could create a shield that not only protects him from physical attacks but also nullifies ninjutsu to some extent.
In Naruto and Sasuke fanfic, Naruto's relationship with Kurama can be shown in various ways. Sometimes, Naruto is depicted as having an even deeper bond with Kurama, where they communicate more freely and work together more seamlessly in battles. Kurama might be portrayed as more of a guiding force for Naruto, not just a source of power.
Naruto would have a different relationship with the other villagers. With Kurama's influence, he might be more aloof or even feared at first because Kurama is a tailed beast. But as he grows, he could use this to his advantage to break down the barriers between the villagers and the tailed beasts. He would be more of an advocate for understanding and co - existence, which would be a significant shift from his regular character development where he was mainly focused on becoming Hokage to gain the villagers' respect.
His training would likely focus more on precision and chakra control from an early age. The Hyuga are known for their precise strikes and efficient use of chakra in the Gentle Fist style. So Naruto would probably be doing a lot of target practice and chakra - regulation exercises, which is different from the more brute - force - oriented training he had in the original series.
His training would likely be on a much grander scale. Instead of training with Jiraiya in normal ninja techniques, he could be training with beings from different universes who are aware of his Omni King lineage. They might teach him cosmic - level jutsu that are far beyond what is known in the Naruto world.
I'm not sure specifically as there could be many different fanfics with that title. It might be about Naruto's relationship with both halves of Kurama, perhaps exploring how he interacts with the yin and yang parts of Kurama in new and unique ways, like in battles or in his personal growth journey.
For Naruto, it would be a whole new experience. He'd be constantly trying to communicate with the mecha Kurama, learning its quirks. Shikamaru might be the one thinking about the strategic uses of mecha Kurama in battle. He'd be coming up with plans on how to best utilize it. As for Kurama, he could be in an internal struggle. Part of him would want to stay relevant in Naruto's battles, while another part would be curious about this new mechanical version of himself and how it could help Naruto in the long run.
Since Madara was very knowledgeable about the history of the ninja world, Naruto's training would include a lot of historical and cultural knowledge. This would give Naruto a broader perspective in battles. He would not only be physically strong but also be able to outwit his opponents with his knowledge. And Madara could introduce Naruto to some powerful allies or places that are related to the Uchiha heritage which could enhance his training.