What are 6'-10" Medium/Fast casting rods (like the Shimano Exage or Duckett Triad) best used for?  Senkos, wacky rig, other?   Seems to be stuff normally served by a spinning rod... interesting size anyway --

I use my medium/fast casting rod for jerkbaits, spooks and poppers. And that's about it 

i use a 6'10 m for 3/8-1/2oz spinnerbaits and topwaters with 12# xt. i don't really fish topwaters enough to justify carrying an extra rod.  this way i can get double duty out of 1.

 

 i used to be a firm believer in using a mod action for spinnerbaits, but i just decided to drop down a power in a fast action to get more bend on the hookset.  so far, it's working out without any problems.

Most anglers find it hard to walk the dog with a spook type bait using anything with a moderate or mod-fast action, that is where that rod comes into play. The medium power casting rods are used for heavier shaky heads, weightless stick worms and other baits you will be using with lighter hooks and line. They are also used by a good portion of anglers with small cranks and topwaters in which they need a little more power than a similar size rod with a moderate action.

I fish baits like larger walking baits and jerkbaits, and fish head spins on mine. 

One used for jerkbaits, another used for light topwater poppers, a third used for senko's and tube fishing, and a fourth for light jerkbaits and crankbaits...it's quite the versatile combo.