Changing the intake from 1.6 rockers to 1.5 will likely give you roughly 0.043" at max lift. But at 10 ATC, the lobe is open about 0.190-0.200" so the reduction in valve lift at that point will be roughly 0.019"
Changing the ICL position 2 degrees will change it roughly 0.015". You can actually make this change now, and see how much it helps you.