How far should I enhance my equipment?

I want to enhance my equipment, but I'm short on parts and materials... Attack and Defense are priorities, and the other three are low priority... but does that mean they're not worth enhancing? I looked it up, and it seems like enhancing equipment up to level 300 and reinforcement level 240 is the most material-efficient. For the main character, I guess I can enhance them that far, but what about beyond that? As equipment level increases, the equipment's unique stats (Attack, Defense) and base stats (Strength, etc.) go up. Reinforcement level applies a multiplier to the equipment's unique stats. Base stat increase values: Satan: 9420 increase every 10 levels (2355 each) Metatron: 16926 increase every 10 levels (4231.5 each) For every 1 level increase after character level 241: 43896 increase (10974 each) Satan's stats are equivalent to 46.5 accumulated levels, which is comparable to a character level +1 increase after level 241. Metatron's stats are equivalent to 25.9 accumulated levels. Even the base stats alone show a considerable increase, so I want to enhance all parts for my main characters who I want to keep alive. However, gathering Adamantite and parts alone is tough, so I'll prioritize enhancing all parts for my main attacker (I'll stop the reinforcement value for accessory head and body at 60 for now).