It's still an open question as to whether a projecting mage's astral form can take a sustained spell. Obviously not a physical spell, and health spells have to be P which rules out options like Increase Reflexes, even if one CAN have a sustained mana spell on a disembodied aura.
I'm of the opinion that since a disembodied aura can be targeted by mana spells (presumably, 6E doesn't clarify this either... have to go off of prior editions) ... it stands to reason that a sustained mana spell could be sustained post-targeting. It should be possible under the Street Wyrd "Design your own spell" rules to create a mana spell designed to do what Increase Reflexes does, but for projecting No-Bodies.
Health spells can be Type M. Resist Pain and Stabilize p. 137 CRB.
Speed of Thought
(Health)
Range Touch, Type M, Duration S, DV 5 + 1 per extra net hit kept.
This spell frees an Astrally projection form from the constraints of the flesh. Your thoughts become actions without that pesky neural transmission lag slowing you down. Add 1 to your Intuition, and 1d6 to your Astral Initiative for each hit on a Sorcery + Magic (5 - Essence) test, only keep as many hits as you want.
Spell Type: Health DV 2
Ingredients: Affect Living Things, Attribute Boost, Planar Effect
Class: General
Could also fluff it as a Detection Spell "Foresight" or some such, different spell description, same mechanics under the hood.
Could also home brew a Metamagic, as it's basically Overclock with Astral Initiative instead of Matrix.
Lots of ways it could be done. Nothing RAW though.