I called Dave from Balsa-USA about building in the correct amount of offset. He is against that, he said you don't need to do that. Dave had me, looking at the plane from the front, put 2 washers under the upper right side, 1 washer under the right bottom & 1 washer under the left top motor mounts. No washer under the bottom left. I am using a DLE-55 & put the motor mounts on with red loc-tite before I put on the sheeting. I'll make any adjustments from the outside if I need to later. I hope this helps. Bob Johnson