Illustrator :: Mesh Gradients Using Pantone Colors

I'm struggling to create gradients for screen printing purposes. The artwork will be printed on 12oz canvas using 3-4 pantone spot colors.
 
1) if I fill an object with a single Pantone color, create a mesh gradient from it using a variety of different opacity settings, say 100%, 50% and 25%, then play around with the mesh handles to produce a pleasant, mixed background, will a gradient of this type work for screen printing? I don't know if a gradient of this type will require halftones, as a linear or radial gradient would.
 
2) it's my understanding that when you prepare artwork for screen printing using spot colors, each color should be on its own layer. In an attempt to add highlights or shadows to an object, if I copy an object and paste it in front of itself, then apply a gradient using another Pantone spot color, say Pantone Process Black(100% to 0% opacity), does it matter what the blending mode is? Obviously you'll get different results based on the option you choose, but again, I'm concerned here only with screen printing. I can then place the gradient on the Black layer.
 
The problem is that I'm familiar with off-set printing, and apparently gradients have to be converted into halftones when screen printing, so I'm trying to figure out the best way of creating shadows and highlights.