Minimum fiend tale completion count in Chapter 1 to get significant awards

There are various rewards such as SP pods etc. as I complete Fiend Tales.

What is the minimum no. of stories to complete before obtaining the more useful prizes in the game? Consider any scenarios where I may need to have multiple SP pods or other rewards obtainable from the story completions.

I don't care about accessories or unlocking new fiends, unless that is a prerequisite for unlocking all of the Fayth Fragments. I would prefer to finish the fiends with fayth fragments asap (in ch.1) if possible, so far I have only done the Flame Dragon.

Also, should I take a break in completing Fiend Tales during game progress? (if say, the time to use SP pods is in future and I shouldn't be using up all available pod slots to get them).

Fiend Tales do not award dress spheres. Some Creature Creator tournaments, however, has dress spheres as rewards.

Fiend Tales award different items, based on which fiend you raise and release. Some unlock new fiends for you to catch, some have Fayth Fragments, some give you very good accessories. Some give you nothing at all. It varies greatly.

Some fiends also only become available as you progress in the story. So, unless you have an idea of what it is you're wanting, there's no real way to tell you how long it'll take to get, or if it's even possible to get.