Hey i am not sure but i would check out the GTO+ instructional videos the are really good. Or post in the 2+2 gto+ thread. The creator is always in there and is super helpful. Cheers

Are you talking about range checking from BB or in Single raised pots as the aggressor.

If you are raiser, set up a sim and give yourself a c bet size or several c bets sizes, whatever. Next, you would then make two node locks: a) you lock yourself for checking range (it is important for the sim to have a c bet size and not just set the bet % to zero) or b) you lock yourself for betting 100% (most people use small bet size options on the flop, you can experiment with different sizes).

Open two instances of GTO+ and look at them side by side.

Disclosure: I am not sure if node locking is included in the free trial.

If you are in the BB and want to figure out a range donk/range check, you would follow a similar approach:

Run the sim with the donk option, save it.

Node lock for 100% bet.

then

Node lock for 100% check.

Take a screen shot of the equilibrium sim and look at the node locked sims side by side and break it down.

Learning how to play prefect vs perfect is great but we are want to know how to exploit (much more profitable as the quality of play gets worse). You will accomplish finding stuff by node locking (if you are looking at sims one by one and not at aggregation reports).