Hi! I'm just wondering if I were to do badly for SPA, will it affect my overall grade for my subject since it is 20% of the overall.
Yes, it will. It can mean a difference in grades of A1, A2 and B3 and so forth.
A 1 or 2 marks difference can make a difference to the grades, and everyone is graded on the bell curve.
Meanwhile, work hard on your theory papers.
I didn't do well for one of my skill 1&2 experiment. Will it be alright if I manage to do well for skill 3?
Just do your best. Listen carefully to your teacher during SPA practices.