I'll tie with bucktail with varying degree of flair, and with flies or jigs. It often depends on the profile and amount of movement I want from the hair so I often have a desired affect in mind when I start to tie.
There is no wrong way to use bucktail, unless you're chopping off the tips to get a desired length, because then you lose some of the natural appearance and movement.
Keep in mind that bucktail is buoyant so the more hair you use on a jig or fly, and the more bulk you add, the slower it will fall for any specific weight. That means a one ounce jig with a lot of hair will fall slower than the same jig with half as much hair. Flair in how the hair is tied, might also improve that slower fall rate since it effectively creates a larger cross sectional area and more drag.
However, generally the hair from the base of a tail will flair more anyway, than the hair closer to the tip of the tail, so that can be factored into how you like to use the hair. I tend to "blend" also to try & get a desired fall rate & movement.
I'll tie some flies with the hair that flairs less, and sparse, such as when tying Clouser Minnows, and use the hair that flairs more on larger jigs where I may want the added bulk and more buoyancy.
Then of course there's the collar shape on a jig that can also cause more or less flair.
IMO, there can be very good reasons to tie with a plan, so you use the hair you have to the best advantage for how you want the fly or jig to appear and to act in the water, which frankly a lot of folks don't give much thought.