You're probably good where you're at, but a taste more would be better. If you have an eighth, see if you can get another and run with it.

As far as the wood is concerned, if you paint all of the exposed wood flat black you'll never be able to see when it starts to charcoal.[8D] Out of sight, out of mind as they say.[X(]

I'm sorry, I couldn't resist that 3/16 to 1/4 should be fine.