I am not sure you really need more elevator throw. Get up high and do a loop, that will tell you if you need more elevator.
If you have enough elevator to fly the airplane you have more than enough to take off.
Grass field? Need cutting?
How well do your wheels roll? (they need to move freely)
From your description it almost sounds like you didn't get enough speed before trying to lift off.
I use full throttle on takeoff on most of my planes and reduce after I get in the air.