In my (quite vast competitive tournament) experience, Apostle's Blessing is very good in turbo builds: because you can play it of the Nexus, which is almost useless as a mana source otherwise. Often you can't squeeze in a win just because Nexus doesn't give green, and here Apostle's Blessing really can take you the game. Also it's quite versatile, and in a turbo build your life total isn't a concern at all. Back in the pre-MH days I used to play 3-1 split with Vines, for the same reason as you cut one here. Also I think 1x Become Immense is very good, but that's another thing.
for every meta I've played infect, despite whatever tech either for us or against us, whatever card--there's really something powerful about plain ol UG infect just quickly killing your opponents on turn 2/3.
Would you try a bant build with Skrelv, Giver of Runes and Flair of Fortitude? I also think that Strix Serenade will be a really good Sideboard Card for Infect
How often is Chalice played in Modern? Because this absolutely folds to Chalice on 1. If it sees any play then maybe a couple copies of Boseiju in the 75 would make sense.