Yes it does help.
If you choose not to listen to 3 AcesHigh Trainers (and me, but hey, what do I know...) then I don't know what to tell you.
(what do the 4 of us have... 50-60+ years of combined experience in WW2 flight sims?)
Why even post if you are not going to listen to the advice of people that KNOW this stuff?
Think it through. (he says trying one more time to make 'em understand)
100% max deflection is just that. MAXIMUM deflection.
If you do not trim and have to pull your joystick back 2 inches to reach max deflection, or you manually trim and have to pull your joystick back 1 inch to reach max deflection, in either scenario you are still ONLY GOING TO REACH MAX DEFLECTION.
Trimming your elevators (or rudder, or ailerons) all the way up will not suddenly make your plane achieve more than MAXIMUM deflection.
If you THINK it helps then hey, keep doing it. It isn't true, factual, or accurate and hurts your planes over all maneuverability in a knife fight; but if fiddlin' with manual trim in the middle of a dogfight makes you
believe you are maneuvering better then have at it.