High Speed vibration, can't find what's causing it.

I always have the weights on the inside of the wheel so they can't be seen . I put the silicone heavily around the sides of the weights and a little on top.
It may not look pretty but you may need to balance both sides of the wheels. On my 72' Dodge van I insisted on the weights be put only on the inside also. Had a top-in vibration and had to allow weights on the outside also to rid it. 295/50/15 TA's