I'm following this build: https://gwpvx.gamepedia.com/Build:Rt/any_Spirit_Spammer
Looking at the description of "Aptitude not attitude", can I still add this inscription on top of my current weapon or will it not helped and is the staff already maxed out?
That staff (or any weapon) cannot have an inscription added to it unless it has an inscription slot. It would read "Inscription: " That said, neither an adept staff head nor an aptitude inscription are much help for a spirit spamming build, as most of the skills used are spirits (not spells), and are thus unaffected by mods that affect spells (additionally, two of the spells in the given build have a 1/4s cast time, so the mods for reducing cast time are largely unneccessary).
However, the mastery wrap is fine, as those will affect all skills of a given attribute (not just spells).
For Spirit Spammer my personal (and in my opinion best choice) is to have a staff like the Phoenix Retribution.
It adds Channeling Magic +1 (20% chance) to boost the invocation of spirits with an extra level (increasing the health and damage they do). This staff is very cheap in the market, you can buy one for 2 ectos.
And as Unholy well said, the "casting time" mod in this case is useless, because spirits are not spells, so instead wasting 2 slots of mods with casting time, use a +5 Energy and +30HP (like the Phoenix Retribution). Also, the inherent recharge time of the Phoenix Retribution helps to recharge, for example, Boon of Creation, Painful Bond or Summon Spirits.
