I've now taken Helms advice, or rather just multiply the foreground tiles with 58,105,139 to get a background palette with a blueish tint.
I suck at picking out colors manually so I'd rather trust automation to pick colors for me.
While going through my files I found the setup file I used for creating the tile grid that I've used. I figured someone might find it useful.
Step 1. I first started drawing the layout of the screen at 1/8 the size before resizing it to 256x192.
Step 2. I then created an area 6 pixels smaller from the edges.
Step 3. After that I created an area 8 pixels even smaller.
Step 4. Finally I applied a 8x8 grid on top of the whole screen.
With this setup I could get a quick start and continue drawing the actual tiles in Pro Motion with the Auto Tile Completion tool.
The plan is to create most of the map using a simple bitmap and have a translator create the final map file.