Lines for light rods in the midwest
Interesting pattern developing here in the midwest--the use of troutspeys with tips to fish moderate distances, depths and rivers with tips for steelhead. My experience is that the most effective way to fish these in the winter, if you mean to fish streamers and not nymphs/indicators, is not casting from the tip with a light line. For me, what has worked best is the Skagit casting approach, because these rods simply lack the power to pick up and cast long heavy lines and tips at a distance, and the light lines and tips simply don't get down enough. I recommend taking a look at Ed Ward's posts about fishing this rod with Skagit lines. You can handle a heavier line if you shorten the line length and load deeper into the rod.
For lines, I've had good luck with the 'quick-n-dirty Skagit formula--using a WC tips line 1 (or 2) weights heavier than recommended for your rod and removing tip #2 (middle), and fishing it with the factory tips or making your own. You'll be surprised what a decently heavy tip and short belly you can hurl with these rods. The short heads are easy to lift and cast with little backcast room, and you can manage depth with your running line.
The way I see it, you want good mass in your tips to sink flies, especially if they're decent sized. I'm not talking sink rate here, just weight/mass. If you're fishing flies that are 6s or 8s or smaller, the light tips on the light lines will do fine, but the bigger the fly, the more overall mass needed in the tip to turn it over and get it down. Second, getting tips up is easier with shorter bellies. Third, the bigger belly of an oversized WC will let you step up to the #8 tips.
I'm fishing a WC 9/10/11 belly (no tip #2) with tips on my Meiser 11'7" 5/6/7. It's heavy but boy does it go!. It lets me fish tips that are 10gr/ft, with overall weight at 480 grains, which I think is right at the size of the line Ed Ward (Riveraddict) used on the rod you have when he fished that model last spring (and gave it high marks). I suggest looking up posts by Riveraddict under the topic Trout Speys. BTW, such a line based on an 8/9/10 would weigh 420 grains, and one based on the 7/8/9 would weigh 367gr. You can make custom Skagit tips from the Airflo custom cut tip that is 20' x 200gr. with a 7.5 ips sink rate. I got mine from MJC and highly recommend him.
FWIW, if someone is dying to fish T-14 on a trout spey, you should take a look at the Rio spreadsheet Bob Pauli put together a year ago. The lightest WC belly to put T-14 on is the 9/10/11, and that's still a slightly reversed taper. To give you a comparison, the average taper between sections on all of the Rio WC lines is about 2 gr/ft. The WC 9/10/11 belly is 13.91 gr/ft, and the T-14 is 14 gr/ft of course. To go lighter, I'd recommend using those Airflo T-10 custom tips if you want to make your own. You'd have good taper/turnover with the WC 8/9/10 and 7/8/9, and again a slight reverse taper using the 6/7/8.
Happy hacking!
Carl