I had tried your tech of attaching legs rather than holes in the bodies. I failed to get them splayed out sideways but had them out the bottom and rather than pop well the legs would cause the popper to come up rather than pop down. Yours oughta work fine, my bad. Your attention to neetness and detail leaves me way behind. Really great eyes. They look "factory" perfect. Your hooks tangent to the bottom of the body makes them easy to pick up off the water and work great casting for sure. I like the traditional splayed hackle tails though, just me.
I wonder when you close your eyes do you see spots?
Look at the tie in for the tail of the saltwater popper. Perhaps the reason you have trouble with tying in the legs behind the body is the diameter of the point where the legs are being tied in. If the ribbon of two or more rubber legs is left intact(not separated) until it is all tied in, the legs can be kept more to the side. If the back of the popper is perpendicular to the hook shank and the legs are tied tight to the back of the popper, the rubber legs will tend to splay sideways. If the back of the body angles to a point at the back, it is possible to get the rubber legs to point slightly forward.
No spots unless I rub my eyes when closed. But I do see floaters with my eyes open.