Update.
I took another crack at using the OEM donut gaskets and was able to get them to work using Baktash's method. I sill think a groove in the midpipe for the donut gasket would have led to a better seal, but think I have it done now
I noticed when I took apart the header midpipe interface there were some black lines from the center to the outside edge, this implies there was a leak to me.
I used Red FPIG to get it to hold while I put the midpipe and header together and started on the bolts.
I did have to take my middle Skid plate off to gain better access and that really made the difference this time.
It seemed a bit more peppy, any leak near the O2 sensor would have inhibited performance
Still fine with the sound, but I am sure others would think its too loud.