At heavier weights like a #7, the WF taper is FAR more popular. It will shoot better, enabling a longer cast with ease. A DT line will need more to be aerialised... To be honest there's not much point listing the supposed benefits of either, as you will get a WF line! I can almost guarantee it
I woudn't go for the airflo floater, get shocking reviews in the past and i personally wouldn't risk them. Have a look at snowbee, rio, scientific anglers, cortland or the pirate on here. Won't go far wrong with these manufacturers.