Extreme Harrow Build Confusion

Hey, I'm currently doing a harrow build, it's nothing too serious but I'm trying to push the limits. So much so that this build is a secondary dps build based on Laetum incarnon.

I replaced Harrow's 1st ability with xata so I can trigger Laetum's final incarnon passive "Overhelming Attrition" even though I can crit. As a result of the minmaxes I made, I can get 382.58% crit chance with riven + arcane avenger + 4th ability + crit mods and 41,5x crit multiplier since it is a 3rd tier crit with tenacious bond + crit multiplier mods + riven, all of that provided that I hit a headshot.

What confuses me is that I'm stuck between deadhead and outburst as a secondary arcane choice. By using status based argonak ceramic dagger in the Melee slot with melee influence, I can reach 220 initial combo with initial combo passives + riven + initial combo mods and few melee attacks(required for armor strip already).

If I add Outburst's crit values, I can get 456% crit chance and the Crit multiplier becomes 61x with the tier 4 increase. Is it worth bothering with outburst for a guaranteed tier 4-5 pass(killing 100 enemy with argonak is pain lmao), or would the deadhead's damage bonus be more useful?