Interesting. So you would like to set stop loss per grid trade for selling?

Note that it's already percentage-based.

If I implement this feature,

• 1st grid trade will execute stop-loss based on the last buy price.
  - After 1st grid trade will execute stop-loss based on which price?

you can have multiple options here ,
option 1 :
adding the stop loss configuration to the grid parameters
example
Grid 1 :
Trigger 1:04
Stop Loss : 0.9 from last sell price ( similar to the existing stop loss configuration but using last sell price not last buy price )
Grid 2 :
Trigger 1:06
Stop Loss : 0.85 from last sell price ( similar to the existing stop loss configuration but using last sell price not last buy price )
... etc

option 2 :
change stop loss to have option to use last sell price after successful sell
STOP LOSS : 0.8
Use last sell price : YES / NO
IF No keep the current setup
If Yes bot to update either the percentage to a higher value or store the last sell price from the grid and keep the same percentage

I prefer to configure than automatically update.

Grid 1 :
Trigger 1:04
Stop Loss : 0.9 from last sell price ( similar to the existing stop loss configuration but using last sell price not last buy price )

Grid 1 would not have the last sell price, so it will be something like this.

adding the stop loss configuration to the grid parameters
example
- Sell Grid 1 :
  - Trigger 1.04
  - Stop Loss: 0.9 from last buy price
- Sell Grid 2 :
   - Trigger 1.06
   - Stop Loss: 0.85 from last sell price 
... etc

Right?

yes exactly

I will put it in the TODO list.

Thanks for suggestions @Elmoftakis

Can I ask for a recommended configuration for grid trading?
I've never used grid trading before, but I'm interested.

And in the grid sell configuration, the "add new grid trade" button is greyed out, how can I configure grid sell?
I'm currently using v0.0.77