Yes, you will need to be very careful when making curves, otherwise you’ll need to tweak them and be very careful to use measurements everywhere in formulas so that your pattern will resize smoothly and accurately as you change the size:
These images show a pattern that I made about 2 years ago that I often use to answer questions because I think I used most of the tools in making it and I also used methods to ensure that regardless of the size, my curves come out beautifully 
I have uploaded onto the Pattern Cloud If you can’t find it, I’ll happily send it to you here.