Reading Spark Plugs

It has been 16 weeks since the carbs were rebuilt. It has run extremely well and been a blast.
A few days ago I was sitting for what seemed forever at a light, when I pulled away it seemed to stumble and backfired through the carb or carbs, not sure with the air cleaner on it - but it blew the filter out the front.
The next day on the way home the rpms were very low in neutral, it didn't stall but close, so I turned the idles up to get home.
I noticed the carb/tunnel ram gaskets were seeping gas, so I tightened them up, next day I had to turn the idles back down.
I got new gaskets today and will replace asap.

It seems to not be running the same, but it's hard to tell. When I got to work today somebody told me, "It doesn't sound as loud today." Which left me perplexed, but reinforced that it felt like it was running different - it runs fine but not as much punch to it, hard to describe.

Can leaking carb gaskets also allow air in?

I also read on this forum that tunnel rams need to warm up thoroughly. My chokes have not been working since the carbs were rebuilt, but it has been extremely warm so it didn't appear to be an issue. Could that be a contributing factor?

I pulled the plugs, they all look the same, pics of one attached. How does it look after 16 weeks?

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