It obviously depends if you are flying in manual flight or in automatic flight and whether or not you’ve had the wind shear warning.
In manual flight the wind shear escape manoeuvre clearly state aggressively apply maximum thrust and disconnect the auto throttle. You are merely configuring the flight directors for the escape manoeuvre. a second press of the toga buttons will not achieve anything as you have disconnected the auto throttle.
Also if you identify the wind shear when the aircraft hasn’t you will have to disconnect the system and then achieve the escape manoeuvre. Again the thrust levers will be at maximum. However in this situation the AFDS will not give you escape manoeuvre guidance. That’s up to you.
I don’t think that in autoflight if you have had the wind shear warning that a second press of the TOGA switches will make the aircraft do anything different to what it is already trying to achieve.
The aircraft certainly won’t be attempting to give you 2000fpm if you’ve had the wind shear warning in auto flight.
Having re-read the OM-B Vol 2 it states
“As a rate of climb increases from 600-1200 feet per minute AFDS gradually transitions from pitch to airspeed control etc etc. Which infers that the thrust will be whatever is required to achieve that airspeed control.
just having re-read your post. You absolutely MUST press the toga switches a second time after you have initiated a go around and subsequently encounter wind shear. It is the only way to configure the AFDS system for the escape manoeuvre.
As to your initial question. A single press of the TOGA switches in a normal go around will attempt to achieve 2000fpm. No matter if you are in CMD or FD.