wow these look really nice.

This is my personal preferences though but hope it helps atleast.

1. Personally i prefer gridless, i myself use roll20 for my online games and it applies a grid. often its a great deal of trouble to align those gridlines to the gridlines on the map despite the function to align to grid built in. if i were to choose i would definitely prefer the dark grid over the white grid as it doesnt stand out as much.

2. 10x10 5ft grids are the perfect size in my opinion. if it is designed as tiles that can be added side by side to make a larger map its neither so small its annoying to put together or too large.

3. the maps look amazing, quite detailed. if i were to say a thing it would be that i miss large obstructions like trees for example that blocks field of view. i am a big fan of the dynamic lighting functions and i think it adds to the enjoyment of a map. but that is just my personal preference. (granted what i see on the map tiles you made i see as bushes. outlining dynamic lighting on maps requires drawing borders past which players cannot see and that doesnt work all too well with the kind of bushes that are there.)

sorry if this is a bit incoherent as i just finished a 10 hour d&d session and its 3:30am hehe.