Proportional risk is based on equity and proportional size is based on lot size.
The Copy Trader gives these options:
Proportional risk – 1.0 – I copy the same risk level respective to both accounts.
Proportional risk – 2.0 – I copy double the risk of the signal respective to my account size.
Proportional size – 1.0 – I copy exact same trade size.
Proportional size – 2.0 – double – so if you open 0.5 lots I would open 1 lot