Hey there, fellow Final Fantasy X explorer! When it comes to sphere grid progression, I recommend focusing on developing each character according to their strengths. For example, Tidus is great for agility and speed, so prioritize those nodes for him.

Don’t be afraid to mix and match different pathways on the sphere grid to create unique character builds. Experiment with different abilities and see what works best for your playstyle.

As for side quests, make sure to complete the Monster Arena challenges for some great rewards and tough battles. Also, don’t forget about the legendary weapons and the celestial weapons – they can be a game-changer in tough boss fights.

Overall, just have fun exploring the sphere grid and customizing your characters to create a party that suits your preferences and playstyle! Enjoy your journey in Spira!