What VG/PG ratio does it say on the 10ml bottle?
Will it be harsher?Yes it will be fine but the nic strength wont be the same as you are use too.
No as @JohnNada has said it will be smoother and a lot less harsher on the throat as 3mg - 6mg is more for DTL vaping and 20mg nic salts are more for MTL vaping.Will it be harsher?