You actually require far less help then that. It should be possible to run all of the MSQ duties in an undersized group with some 60s. Done Garuda HM in duo as WHM/Ninja (not super geared, like 170~), so with 3 60's it shouldnt be too hard to do all the duties that dont hard require 8~ people.

I think people in this game are too used to just going DF as ive rarely seen Undersized party been brought up as counterargument to trouble finding groups/long waiting time in queue.