I will try to help, but first we need to get our termonology straight. Right and left is determined
as if you are sitting in the airplane, and looking straight ahead over the nose.
I explained washin and washout before, but apparently I wasn't clear. Let's start with washout,
which is a twist in the wing from root to tip. If we jig up the wing so that the root rib is dead flat to the direction of air flow, then the tip rib will be at a negative angle. This means the leading edge will be twisted down, and the trailing edge will be twisted up. Washin is a twist in the opposit direction. If your left wing trailing edge is 1cm lower than than your right your wing, it is twisted in the correct direction, but WAY TOO MUCH! I'm guessing that you are experiencing an adverse yaw condition which can actually cause your airplane to turn in the opposit direction of what you would expect. Another problem is that if your left wing trailing edge is twisted down, so you have washin in that wing. Washin is generally an unstable trim technique, and should be avoided most of the
time. (There are exceptions to this rule) Most full size airplanes are built with washout in both
wings because it makes the airplane more stable when approaching a stall. As the angle of attack
of the wing increases in a steep climb the root (or center) of the wing will stall first, and the tip
of the wing won't stall until the nose is raised even higher. This helps maintain better control of the airplane through the stall, and recovery of control after the stall.
Your question that for "washin the left wing tip should be higher, not lower?" makes me think you
are confused. Washin and washout has to do with the the DIFFERENCE in the angle of attack from
the center of the wing to the tip of the wing.
I had to go check my Freedom Flight instructions to confirm what the recommendation was, and I
find it confusing. The picture on page 8 is a HEAD ON view. The notation is on the right hand side of the drawing, pointing at the LEFT wing, and says "Wing should have a small amount of 'twist' or
Wing Warp to keep wings level in turn (left wing down) THAT MIGHT BE CLEARER IF IT SAID "LEFT WING TRAILING EDGE DOWN"
The next thing you said is that the FF instructions say that "the leading edge of the wings are level,
and the trailing edge of the right wing should be 1/8" lower.(Or to put it another way the right wing
would have washin). I didn't want to take the time now to research the instructions, but one of two things are going on, you have misunderstood the instructions, or it's a misprint. You want the opposit twist. When viewing the airplane from the tail (looking in the direction of flight) you want
the trailing edge of the right wing to be 1/8" higher than the leading edge. The twist should be a gradual change from root to tip, with the 1/8" amount at the tip. If possible it's almost always best
to use washout instead of washin. Therefore, if possible, try to twist the right wing trailing edge
up, instead of twisting the left trailing edge down. Now in the real world this doesn't always work
out! Our wing structures are not very warp resistant so most of the time when you try to twist one
side of the wing one way, the other side tries to twist the other way.
Now if you are not totally confused I will put it in as few words as possible. When viewing your
airplane from the rear you want the right trailing edge at the tip of the wing slightely higher than the leading edge. Not quite as desirable is to have the left wing trailing edge at the tip to be slightely
lower than the leading edge. Good luck