What I am having problems with is trying not to over spend on a unit with in my Nurgle themed foot slogging army

The problem I find is you need a herald with a locus and wizard lv 1 and in say a 2000 point game the Max you will ever get is 2 = 250 points each. So that means my army will have its two core units but now the problem is daemonic brake test having too many in a single unit if they fail combat will result in wiping out the hole unit so they can't be too big because rolling double six means good bye unit so how could I work around this?

I feel having two units of 27 + a herald of nurgle is too much or too little not to sure...