I'm unsure of the the advantages and disadvantages over the standard flat felled seam. Although I believe, and could be completely wrong, that warbonnet tarps are done with the French seam with bias tape over the seam itself.
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Another option from DIY Gear Supply.
I like DIY gear supplies "hybrid" seam--------I think I'll give that a try---thanks guys!
Here is a little diagram from my notes that may help show the difference in the seams…
Attachment 43773
And one more type of seam…
Attachment 43774