Make sure you use a Water-based Poly over Latex paint.
Oil-Polys are fairly amber.
Water-Polys are clear.
Also...when painting over:
* You'll have to feather-sand all the "stripe-ridges".
* If you don't, you'll always see the profile of those stripes.
* You MAY also still see their profile...even if you do sand all the edges, since there's a different thickness where the stripes are.
* They won't be visible straight-on typically, but at some angles, you may see them.