[kupoartist]

As you enter, you'll find DJOSE SPHERES on the left and right walls of the
chamber. Insert them both in the door to open it. You'll enter another chamber.
There are a load of symbols on the floor, your job is to light the lot of them
up. You'll see a pedestal, and a door beyond it. There are DJOSE SPHERES on
either side of the door, take one of them. Run to the right and you'll see two
more holes in the wall for spheres so put it in either. Now take the other
DJOSE SPHERE from near the door and place it in the other hole to the right.
A pedestal on the ceiling will light up. Now go to the pedestal on the ground
and push it under the one on the ceiling (it must have a DJOSE SPHERE in it).
The DJOSE SPHERE will charge itself up. Take it and place it in the hole to the
right of the door.

The door will now open, but the way is still barred by a pit of lightning. Go
back to the pedestal on the ground and put a DJOSE SPHERE in it. Now push it
into the lightning pit, creating a platform. Use the action button to jump onto
the platform, then to the other side. Push the switch to light up a piece of
the rune on the floor, then head back to the main chamber. Take the charged
DJOSE SPHERE from the right of the door and put it in the hole on the left.
Now run the the left and step on the shiny spot on the floor to get back the
pedestal. Take the two remaining DJOSE SPHERES (one in the pedestal, one in the
wall to the right) and put them in the holes back in the walls of the first
chamber of the trails you entered. This should light up the remaining parts of
the symbol on the floor. A platform will materialize so jump on and head up.

Run north to a room with 5 pedestals, each in an alcove in the wall. Push each
one into the wall as far as it can go to create a flight of stairs an pedestal
near the platform. Don't go up yet, head back down on the platform instead.
Near the shiny spot to the left a Glyph has appeared on the wall. Touch it to
find a DESTRUCTION SPHERE. Now go back up on the platform and insert the
DESTRUCTION SPHERE in the pedestal. A secret chamber will appear, take the
MAGIC SPHERE from the chest. Now go up the stairs and complete the Trials.

- From a PAL FFX guide on Gamefaqs

I know this one is a pain isn't it? some of them get really obscure, and bear in mind there will be more... good luck ^_^

As for the luck spheres... i'm searching myself, and apart from sometime at the beginig of the game, I haven't seen any (or an ability that gives you them :/ )