The placket with fusible interfacing didn't work out for me, so I used the first one I'd made. When I sewed the placket with the fusible interfacing, the fabric at the end of the opening which meets the 'tower' could not support the stress. The tower curved on it's own. I tried to reinforce the tower with a criss-cross quilting stitch, and while it helped somewhat the bulk of the placket increased too much.
So here's where I'm at:
This shirt needs hems on the sleeves and a bottom hem. I've learned a lot from the shirt. For starts, I won't use a sewing machine again for spandex. When I do my next jersey, I will use a serger for seams and a coverstitch for hems. I have a little more learning to do with this jersey