I always wrap mine with sinew as well Pat, but sometimes they lift in the middle anyways, especially in the heat
What I have been doing lately since I have been wrapping is.....
..Trim the wild turkey feathers close to the final size and cut them to length
..Use a fletching jig and very little super glue at the ends of the feather only
..Use upholstery thread and wrap the feather on from front to rear. this sometimes breaks loose the super glue which is OK.
..adjust feather to get it straight and spaced evenly.
..Trim feather to the final shape and make sure the spacing and straightness is OK.
.. Finally water down some TBIII and use a small paint brush and paint the wraps between the feathers to secure everything in place.
I'm not the best explaining things in print, I'm better showing in person, hope you understand the written words.
DBar