RE: Mounting the Engine at a slight angle.
pdm,
You beat me to the punch. Many of us are so used to seeing this question, we stop reading the entire question.
Don,
I'd try flying it and see if there are any bad habits, probably not, just not optimized. You would have difficulty in redrilling, but may be able to egg out a hole, fill with epoxy & filler, then redrill to rotate the engine a bit.
Jack