I also built this plane according to the plans and it takes off and land just fine. I am running a OS FT 160 twin in mine and I love it.
This plane has such a long tail on it, which makes it easy to correct any thrust from the prop on take off.
I would not change anything from the drawings, remember SIG did not just through the thing together, they have spent hours testing and engineering their planes before putting them on the market. Just because someone else’s plane needs two degrees to the right doesn’t mean this one does.