Yes it's OK. Sometimes I will try to design a knife to look good while in the sheath too. If I have a dropped choil, I have to make the guard asymetrical, being longer on the bottom.
Most of the time part of the guard will stick out, but not always. I would trace it on paper and play around with the drawing. When it looks right to you, it'll be right.
I'd like to see a picture when it gets done. Lin