Best UV Mapping Workflow for Stager?

Just wondering what other options people are using to UV Map models in Stager outside of it's built in Auto UV feature. The results I'm getting from the Auto generated UV Map Export in Stager are just not usable without needing extensive cleanup in post. The model below is pretty much a simple box and Stager still can't create a usable UV map. I get black seams between all of the panels. I use fillets to slightly round the edges of the model so it looks more like scored and folded cover weight paper. I think just the curved edges are blowing Stagers mind. 

Any suggestings for a more effective UV workflow would be great. How can I stage my models in Stager and still get accurate and clean UV maps. I'm not just flooding a shape with a texture, some of the graphic placements are very specific. I need something that won't leave seams between everything. 

Thanks!