Help me pick feats for a Sand Shaper/Incantatrix Sorcerer

[Extra Anchovies]

Purpose: Exactly what the title says. I want some nice metamagic feats, but have literally zero actual playing experience with a metamagic user, so I don't know what to do. So far I have:

1: Sorcerer 1; Touchstone (City of the Dead) [for Sand Shaper], Heighten Spell [human]
[Minor Fey Bloodline Level, to get CL 1 higher than ECL]
2: Sorcerer 2
3: Sorcerer 3; Empower Spell
4: Sorcerer 4
5: Sand Shaper 1
6: Mindbender 1; Mindsight
7: Sand Shaper 2
8: Sand Shaper 3; Iron Will [from Minor Fey Bloodline; required for Incantatrix]
9: Incantatrix 1; Twin Spell [Incantatrix Bonus Feat], Practical Metamagic (Twin Spell)
10: Incantatrix 2
11: Incantatrix 3
12: Incantatrix 4; Split Ray [Incantatrix Bonus Feat], Versatile Spellcaster
13: Incantatrix 5
14: Incantatrix 6
15: Incantatrix 7; Maximize Spell [Incantatrix Bonus Feat], Practical Metamagic (Maximize Spell)
16: Incantatrix 8
17: Incantatrix 9
18: Incantatrix 10; Chain Spell [Incantatrix Bonus Feat], Practical Metamagic (Chain Spell)
19: Sand Shaper 4
20: Sand Shaper 5

At this point, I haven't decided what to focus spell selection on. Any suggestions there?

ETA: Race, for the record, is Silverbrow Human.

[Extra Anchovies]

Would it maybe be worth shoving in Extend and Persistent Spell in the build somewhere, so I can apply Metamagic Effect (Persistent) to the really good short-duration defensive buffs? If so, where? I'd replace either Chain and Easy MM (Chain), or Maximize and Easy MM (Maximize), probably the former. Would it be worthwhile? Persistent Arcane Spellsurge answers that question with a resounding yes, but they may be a counter-argument I'm not seeing.