Unfortunately that Airflo Elite doesn't seem to be in production any longer? A shame if so...
There are two options for DT lines which I know are less costly than that SA Mastery DT; the 406 DT lines and, likely the least costly DT I'd consider, the SA Frequency DT for 49$! But I do prefer the thinner end diameter on the 406 lines -- yet they are 20$ loonies more! -- it is fantastic for creating a smooth transitioning needle nail knot out of your leader's butt end.
Some interesting notes. I became curious about line weights, and decided to check some my fly lines. I had only used a DT, and a sinking tip fly lines on a Fenwick 8'6" 6wt prior to my hiatus to do some sailing. When I went back to fly fishing my fly shop put a new WF6F without asking. My FF buddy was using a 4wt so I bought a Double L out fit from LL Bean, and that came with a WF4F. I never liked the way I flung those lines. I have since refitted with some DT line in both 4 and 6 wts, plus I've added a 5 wt glass.
I ordered a little digital scale that measures in several weights including grains. It is actually hard to be absolutely precise, so I measured the front 30' and marked with a black Sharpie, then wound that onto an empty fly line spool, that I zeroed the scale with. Here are some results (I'm not done, I still have to weigh my 4wts).
WF6F I think it is SA something 168 gn.
WF4F I think it is also SA it came from LL Bean 147 gn.
DT5F Orvis Hydros 150 gn.
DT6F 444 Peach 171 gn.
DT6F 444 Sylk 149 gn.
DT6F 406 160 gn.
The weights of my other lines
WF5F Rio 156 gn.
DT4F 444 133 gn.
DT4F 406 120 gn.