I'm still making maps today and I'm noticing a few slip ups on my tile sheet design. It's all fine and really just minor detail stuff, but I really should have made a few extra pieces that accommodate singe spaces and those rare corner pieces that can link perpendicular angles together. I also had some redundancy issues in that 2D Toolkit allows for flipping and turning sprites which made doing that for some tiles on the sheet pointless. The 3x4 arrangements shown above really aren't enough and I'll more likely need 12 tiles per terrain instead of 9.
For now I'll just work around these limits but in the future I'll need to be sure I have tiles filling in 1x1,4x4, and corner positions. I'll also need to separate each sheet my tileset so I can easily reach all the tiles I could need for a particular area. I should also keep in mind how I could save time by having all the commonly used tiles in different variants(snow version, desert version, grass version) placed in the same position. That way I can swap out the Tile Sheet component and the map editor will automatically switch mapped tiles to match the ones on the replacement sheet.