Spear will affect Elixirs field on mnk 100% (they changed the duration of spear to 30sed right?) And 50% chance it affects both elixir field and howling fist. Then we have couple of stuns that are ok quite fast CDs so might affect them too. So ever so slightly dps boost possibly. And if there is a downtime within the fight where you can't keep GL3 in anyway or form thworing arrow on the mnk will get him back to full dmg slightly fastet (and shouldNT have tp issues cause downtime. Also note that this applies only if mnk used PB at opener and it's been less than 3 minutes.)

Some mnk perspective I could give, probably I could use Spire in longer fight with less downtimes (if I can't get purification done) so I can keep using ToD easier (cri 80tp) though if the tank has no TP use it on tank. I will eventually have invigorate up and/or brd will be singing anyway