Using Two Max Out Cores, Two Ultimate Perks.
In the end, Stark decides to select [Crimson Spears] and [Asura's Arms] as the skills he would max out with the [Max Out Cores].
Here is his thought process.
Aura Smash could have a perk too difficult for him to wield, it already happened twice already, and going from level to who knows what seemed too much for him; don't get him wrong, it is an incredible skill, but he is satisfied with it right now.
Heaven's Wrath felt like it wouldn't go past level 30 in terms of max level, after all, what else you could bring to this beam that erased everything that entered it?
Crimson Ball Transmission was useful in battle, but just like Aura Smash, he had the very deep impression that using that ultimate perk would be hard to master as well.
And as for EGO, well... he just didn't feel like it, as both he and his clone could use it, and a week between each use wasn't necessary right now, it was already strong enough as is.