Discussed pretty thoroughly here:
http://www.ffxiah.com/forum/topic/3634/sch-merits#130751
Ultimately it will come down to your play style, party vs solo.
Personally i wouldn't bother with sublimation merits, it's essentially a longer charge time for an extra 50mp, you would be better suited just riding it using as and when its up. Rather go with modus veritas merits ↓
Helix does 100 damage in 10 secs (10 dmg/sec)
Modus Veritas Helix does 100 damage in 5 seconds (20 dmg/sec, doubles damage with a duration reduction of 50%)
1 Merit Modus Veritas Helix does 120 damage in 6 seconds (20 dmg/sec, doubles damage with duration reduction of 40%)
2 Merit Modus Veritas Helix does 140 damage in 7 seconds (20 dmg/sec, doubles damage with duration reduction of 30%)
3 Merit Modus Veritas Helix does 160 damage in 8 seconds (20 dmg/sec, doubles damage with duration reduction of 20%)
4 Merit Modus Veritas Helix does 180 damage in 9 seconds (20 dmg/sec, doubles damage with duration reduction of 10%)
5 Merit Modus Veritas Helix does 200 damage in 10 seconds (20 dmg/sec, doubles damage with duration reduction of 0%)
I would then consider
3/5 Enlightenment, quite a bit of utility in this, not so much so that you would need it at a 5/5 frequency. Which leaves you to add a few merits to
tranquillity and
focalisation for situations that would require them, not necessairly spammy stratagems.
5/5 Stormsurge definitely.