First number : - number is top left half of map , normal number is top right half of map
Second number is either bottom left -number or bottom right -number, or
So -38 (ignoring middle number) -1300 would be the bottom centre of the map as the numbers go from the middle of the map to the outside of the map, and 204 (ignoring middle number) 1664 would be the top centre,
So 760 (ignoring middle number) -600 would be about halfway down the right hand side of the map,
and -1468 (ignoring middle number) 348 would be about halway down the left hand side of the map,
You can get a good idea by just right clicking your mouse over the RustIO map and it will show RustIO grid and coords,
I always go right around the map (after wipe) and /sethomes in each corner and bot/mid/top of map to get to airdrops faster.