I'd use a grid of dashed lines in transparent white, instead of solid black on your second floor - to prevent the clash.
Hugely improved Meek!
- desaturated office floorboards on the daylight maps look amazing - great job.
- your light looks excellent, particularly in the office. The sickly green tint is gone and now it looks natural.
My only comments are: I agree with you that the map would look just as good, perhaps even better, without the light. And the upstairs grid, while at least not aggressively unpleasant anymore, does clash with your floorboard texture. You need to find another way.
I don't use GIMP, so am unsure if it can't easily do dashed lines. I use a vector app and dashed lines are built in. However, working with non-dashed lines of transparent white works - so stick with that.
Gimp (like several raster-based programmes) has a problem with dashed or dotted lines. It can be done, but you need to work against the programme, rather than with it: try googling 'dashed line GIMP' and you should find plenty of tutorials. It might be easier to use a very thin white line set at 70%-or-whatever opacity instead.