I make blends all the time for my Volcano. I have a Sativa blend, Indica blend and Hybrid blend...all with excellent results, and I have mixed Indica & Sativa strains with wildly good buzzes....only once and a while do I just do one type of bud (that is after the initial taste)...I love my blend and keep them in glass jars and use a cappacino spoon to fill the Volcano.
Yes, all the time. I rarely use a singular variety unless I'm trying to get an accurate estimation of the taste and effects from a new variety. Also, I find it helps curtail tolerance and enables one to "customize" thier stone to some extent.
Making blends is the way to do it, the combinations sometimes seem to yield entirely different strains.
One of my buddy's cousins would keep a whole variety of strains in a tacklebox in his house. Anytime someone came over that was a new smoker, he'd bust out the tacklebox and mix up something special for them. He was a master of mixing strains for different effects. I'd love to get to that point someday- where I have 10-15 strains on hand at any given time and be able to mix at will.