Lots o' Arrer I only use in two ways: when I need to deliver some damage and all other abilities are on CD. It's even castable on the move, it will get aborted immediately but it still applies one tick of damage which can make a difference. Otherwise I only use it in very stationary fights where I can't reach the target with other abilities.
I rarely use plink in sieges or other stationary fights where I can not reach the target with other abilities.
What Blocka is really nice and I try to use it when I know that waiting for the 2s (or 1s?) cast time won't be a disadvantage to me (i.e.g some melee will reach me when I stand still). It's a good debuff.
When I know a WH is about to attack me I try to activate squid frenzy and sometimes even pet disarm in advance.
Otherwise I try to keep squig frenzy on CD. I try to never use pet m1 without squig frenzy combined so sometimes I wait until m1 is ready.