For me, I think that I'll just strap on the type 8 tip for most scenarios this year on the vedder. Maybe move up to the t14 if a run has a lot of funky hydraulics that will push the fly up in the water column. The difference between the two in terms of sink rate isn't a whole bunch, but what it will do is keep your fly down better once it actually gets there.
With the lighter tip, you'll probably be able to bomb a cast further, getting the fly to where you have time to let it sink and exit into the swing at the proper spot. Often this is casting to the far shore into the gut of the run, letting it sink and then your fly swings out perfectly into the slower water where the fish are sitting. If you're struggling to get your line out far enough into the run, you're simply sinking it on top of the fish and missing the presentation. That being said, I remember reading something in Dec Hogans "A passion for steelhead" where he talks about presenting a fly's broadside. So you may want to look into that.
Some people swear that to "be in the zone" you have to be tapping bottom from time to time. Their success could come in two ways: Some of these guys could very well be flossing up their fish rather than enticing them on the swing. (I'm sure I'll stir up a storm here.) Or they use it as a reference.
Often winter water is coloured and you just don't know if you're fishing 3 feet, 6 feet or 10 inches for that matter. So this is where the tapping bottom part comes in. It gives you a reference point. If you hit bottom with fly "a" and t14, lighten up a little and you should put you right in the zone.
That being said, I find determining depth in a colored river to be one of the more difficult parts of steelheading.
Fish typically hold in the bottom foot of the water column and can see a whole lot more looking "up." Why not have your fly swinging 6 inches above their heads than bouncing it below their chins? I don't really like decorating the bottom of a river with a fly that took me 20 minutes to tie, or in another's case, 3- 5 bucks to buy.
Anyways, that's my interpretation. Take what you will from it. I've only ever shook hands with one vedder steel on the fly.