I think part of the issue here is trying to translate the "rules" (as if there is any such thing) as they apply to DT line use in trout fishing and then speculating on what the advantages may/may not be for smallmouth bass.

Personally, here's how I look at it as a smallmouth angler. Basically, unless you really need something to fool around with, this "issue" isn't really worth expending much brain wattage on. The advantages, if there are any at all, are likely to be miniscule at best.

IMO, most of what goes on in smallmouth bass fishing, involves the combination of finding out what fly and presentation the bass will hit and that involves first finding the bass period. These two "simple" things alone are almost a full time job.

OK, so let's say now you're standing there ready to cast to a likely bass feeding or holding spot. Great. Effectively, I'd say there's about a 90% chance that whatever cast you use, overhead, roll, spey, or a modified flim-flam cast with a twist of lemon, the biggest factor that affects accuracy and distance is usually the size and wind resistance of the fly.

Most of the time I'm chucking big, wind-resistant flies so really the taper of the line is going to have minimal impact unless as others have mentioned, you need to go beyond 40 feet in which case the advantages of the WF start kicking in to some extent. But then throw in a modest crosswind of 10 MPH and you'll see why I think the line taper isn't really where I'd spend a lot of time.

Grouse