Would love to see a way to make the smoke go higher/last longer. Whether that is through some in game method, like campfires with haybales, or simply through the config.

It was added in the 1.1.0 version:

• Chimney that has another chimney underneath will now emit a Signal Smoke (like a hay bale under a campfire)

Seems like I forgot to mention it in the description. Should probably fix this.

Haha ok, just tried it out.

Only minor suggestion, it would be nice if when they stacked, they connected better. Like with the brick/stone chimney, the bottom one should lose the lip around the top to connect cleanly with the one above. The lower terracotta one should become a full block, etc.

Yeah, that would be nice. I'll do something like this next time I'll have time to work on a mod.