Which line and/or amount determines EI repayment and how much is the threshold for repayment (I am trying to determine an amount to invest in RRSP so that I am under)?

EI recipients must repay a percentage of their EI benefits if their Net Income - Line 236 for the year exceeds a threshold amount. The repayment is 30% of the amount by which their net income exceeds  $64,125 in 2017, or $64,625 in 2018.

All first-time claimants and EI special benefits for sickness, maternity, compassionate care, or parental reasons are exempt from this benefit repayment.