Two schools of thought on PvP boners. Max block is usually done with Stormshield (Ber it. 43% DR when Ber'd. A total of 51% with Enigma). Or max vita with Spirit monarch for the fcr/fhr. If you have really good PnB life charms, then I would go the max block route. If not, the you probably need to go max vita otherwise your life will be pretty low (and try to get some DR by wearing Verdungos and/or Ber'ing your helm).
Having maxblock on a necro only makes yoru necro stronger. It allows to have a huge advantage over barbs and helps alot versus smiters/melee characters in general. A necro with decent life charms, maxblock, and bone armor is an extremley durable character. Heck, I don't even have a CTA or lifers right now and I pwn alot of people in pubs. A fully decked out maxblock bone necro played well is one of the best duelers out there.
What is your life? I know that a necro gets low return for vita points, so max block is ideal, but I only have skillers with no major secondary mods. Would going maxblock without life skillers hinder a boner?