Persistent damage is calculated as if it proc’s 3 times on average. Extra damage on a critical hit is not factored in.

NormallyExpansive SpellstrikeSpell SwipeEasily accessible for MagusRankingWhy?LevelDamage typeAverage Damage on successAverage heightening damage bonus per level on success
Divine LanceLikely notThe damage is poor, but it can be desirable to pick up Spirit damage.Cantripspirit52.5
Gouging ClawYesIt’s your highest damage cantrip option for SpellstrikingCantripslashing or piercing, plus persistent bleed133.5
IgnitionYesDecent backup option for Gouging Claw. Careful for Starlit Span, targets are not in your melee range, so this spell deals less damage for you.Cantripfire73.5
Needle DartsNoGouging Claw is better.Cantrippiercing7.52.5
Slashing GustNoWith one hand and without Spell Swipe, Gouging Claw is better.
With Spell Swipe, you likely can’t afford to have two hands free, and you likely want to invest to get access to Imaginary Weapon.
Cantripslashing52.5
Tangle VineLikely notGood control option to keep enemies out of melee, but you’re a martial. You’re already in melee. You also likely don’t have the Spell DC to make this work. Slightly better for the Starlit Span.Cantrip---
Telekinetic ProjectileLikely notGouging Claw and Ignition deal more damage, and you likely don’t need the extra bludgeoning damage type.Cantripbludgeoning, piercing, slashing73.5
Fire RayYesHighest damage, does area control that works with Reactive Strike. You have to pick up Cleric Dedication.Focus 1
Hand of the ApprenticeMaybe?Weapon scaling is great, but your spellcasting modifier isn’t. Good way to gain access to critical specialization effects though, and Wizard Archetype is good anyways. And you also want runes for additional damage on your weapon.Focus 1
Hurtling StoneNoAdds a little bit of a control option, but the damage isn’t greatFocus 1
MoonbeamLikely notThe damage isn’t great, but silver damage is kinda nice in the right campaign. Dazzling is only a minor bonus.Focus 1
Malicious ShadowNoUnknown how - and if - this works with Spellstrike.

Technically it fullfills all the requirements for a valid target for Spellstriking (requires spell attack roll, targets 1, 2 actions), but requires GM fiat if the shadow is just flavour or not (in my opinion, it’s not flavour). If it isn’t, you’re not the one making the spell attacks, so it’s not valid.

But really, you don’t have the actions to sustain ánd continue Spellstriking, so if you really want this, just play a Witch.
Focus 3
Hydraulic PushYesGood damage.
Blazing Bolt
Exploding Earth
Spiritual Armament
Splinter Volley
Chilling Darkness
Holy Light
Disintegrate
Blazing Bolt
Exploding Earth
Spiritual Armament
Splinter Volley
Chilling Darkness
Holy Light
Disintegrate