I process the bottom snr mic completely different than the top. Basically the bottom just has a bit of compression(based on how long you want the sizzle to last). There isn't much body in the bottom snare mic compared to the top, and i usually have it a few db(or more) lower in the mix, depending on how you want your "sizzle to body" ratio. I also do a small amount of eq, mainly to the high end, but it's nothing major and it can vary quite a bit from snare to snare. Just make sure your bottom mic is in phase with the top mic. Easiest way to tell is to just zoom in really close to the wave, and see if the waves in the two mics are going up and down together. If one is going up while the other is going down, then they are out of phase, and you'll either need to scoot the bottom mic wave to the left/right, or (most likely) just need to "invert" the entire wave.
This is how i process when i'm making snare samples though, so i can do as much processing as i want without worrying about cymbal bleed.
I'm not sure about you guys, but the bottom mic does't seem all that important in the overall sound to me. The room and overheads seem to have the biggest impact.