Hi!
Agree!
The first thing you should check when trimmining an airplane is always the wing! Does it have wash-out or wash-in or is it built straight?
The second thing is always to set the aileron,elevator and rudder straight and use as small trows as possible but using as much trow on the transmitter as possble (100-150% if you are a JR or Spektrum flier)! Never reduce trow elektronicly,at least not much.
Then you fly the plane!
Be careful how the plane reacts!

The goal when trimming all planes is to use as less elevator and aileron trow as possible and still be able to stall (and controll) the plane when you want to at very low speed.
The plane should not dip it's nose at low speed ,it should stall over it's wing tip!! But it should do so when you want it ,and do the same whenever you give up-elevator att low speed. That's very important to remember!
You check for correct Cof G by flying the plane straight ahead at full speed and then do a 90 degree plylon turn (just using aileron and elevator) . The plane should just float through the turn without dropping it's nose! If you notice a slight tendency to drop the nose the plane is nose heavy!