Brent, that unsupported "wing" on your current counter, I assume you are recreating that with the angled area on your pattern. I am not expert, but would think it can't "hang" like the current counter top even though there is wire in it. Some type of support brace front and rear from the counter to the wall is going to be needed.
Are you going to leave the wire in the pattern and pour or are you going to pour then vibrate the wire in. Hear it is a bummer when you vibrate the wire to the pattern's bottom so it shows up in the top of the counter. I have considered building one of these from time to time and figured I would use string and fender washers so I knew when the wire reached the center.
I don't know about the exertions of the concrete, but a diagonal brace inside the sink cutout would insure no unwanted angles.
So, adding color? Hope you take pictures and document this as you go. Would really find it interesting. Good luck and have fun. If the first one doesn't work out, going to put it out for a flower bed?
God and family, the rest is icing on the cake.
I'm so far behind, I think I'm in first place.
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