New laser built need X and Y information

I built my own laser that has a workspace of 800 x 200. I’m using the Blackbox x32, Nema 23 steppers, proximity limit sensors and a laser tree 30w diode module. I’m using Lightburn software. I understand Lightburn works in positive space. My machine homes to the bottom left. The Y limit is mounted on the front or at least what I call the front, and the X is on the left. The X runs from home to the right displaying positive movement the Y moves aft displaying negative movement from home. Home shows 0 on X and Y. Is there a Grbl code to change the negative Y movement to positive without changed the actual direction? I don’t usually go to forums because searching always seems to show a solution. Is it a matter of relocation of one of the limit sensors? I’ve used the G10 L2 P1 x-800 y-200 in Lightburn, is the “dash” in the code for negative coordinate, can I use x800 instead? Any tips would be appreciated. I used the custom machine in Lightburn because the grbl option would not connect. Every function works, laser fires, X and Y move fine, homes where I think it should. It just seems like it has a mind of its own in Lightburn. I blew through the free trial getting it setup, I did buy the license because it will work for what I need very well.