Sphere Grid Development

So, how do you like to develop your characters after they've finished their own area? Do you keep them on the rails, or do you use friendship/teleport spheres to develop them a little differently?

Tidus: After he's finished his own skillset I move him backwards through Auron's to pick up that cluster of Strength +4s and some extra HP.
Yuna: Move her onto Lulu's! She's got plenty of MP and Magic, the best thing to do is to boost those stats even more and pick up some Black Magic along the way
Rikku: Rikku is just as speedy as Tidus, so I like to have her learn his abilities and pick up even more speed to make the two of them an unstoppable hyper fast machine! Moving her through Lulu's is pretty pointless as Lulu and Yuna will ALWAYS be way better at it.
Lulu: Same logic as Yuna above. Not only will I have two white mages, but Lulu will stop being so goddamn slow. BURN THINGS FASTER
Wakka: Wakka is just fine spilling into Auron's grid. Keep on truckin'.
Auron: Also fine. He's the slowest party member, so picking up some of Tidus's speed is a great idea.
Kimahri: I just have him pick up everything in his own area, and then I either move him through Tidus or Yuna. idk

Give Yuna and Lulu a couple of black magic spheres for Osmose, and you're all good to go!

At that part I pretty much just drop Lulu as she is useless for the Monsterfarm sidequest... I send everybody else on to Auron's grid for massive damage, Auron just goes on and learns Tidus' good abilities. Afterwards I usually send everyone down Rikku's path since Steal and Use are always useful, they get insane speed and actually decent strength too (that +8 Strength at the end there is a blessing).

Edit: Forgot Kimahri. He learns everything around Ultima in plain sight, then he goes down to Rikku's path. It's always great to have another Thief around, plus this comes with the advantage of never having to ever worry about Lv. 3 Key Spheres ever again, as you can steal those from Biran and Yenke. After Rikku's path he also goes over to Auron's like everybody else.
Also, if Lulu has additional Sphere Levels left, I just have her explore the area around Ultima and be the first to learn Ultima once it's possible.

When I played this I was kind of aware of there being a section with no Yuna, so I sent Kimahri down her path. After everyone finished theirs I'd usually just send them in a random direction.