spey machine,
I'm not sure how much experience you have spey casting or the type of rods you have spey cast in the past. However, it sounds like you are expecting the T&T 1409-5 to be a much softer and more flexible rod than it is. It is one of the fastest 2-hand 14' rods on the market, and is a whole lot faster than the Sage or CND rods.
I like the 8/9/10 Windcutter on both the T&T 1409-5 or 1409-3 and it loads the rod very well for me. The 9/10/11 Windcutter is as heavy a Windcutter I would ever use on the T&T 1409. In fact, the 9/10/11 Windcutter overloads the 1409 for me. Remember that the T&T 1409 (whether 3 piece or 5 piece) is an 8/9 rod, not a 9/10 rod.
It sounds like you are wanting the rod to bend into the butt (thus my assumption in the first paragraph about you expecting it to be a softer, more flexible rod) when you're casting and that is why you are feeling like the 9/10/11 Windcutter is underloading the T&T 1409-5. Keep in mind that the T&T rods are faster recovering, stiffer, progressive, and less flexible than most 2-handers pn the market. They were not designed to bend into the butt section unless you are really putting the wood to them for cast out yonder. However, if you use a quick, powerful, and somewhat shorter stroke when casting the T&T's, the rod practically casts itself. Just because you don't feel the rod bending down into the butt section (or even to the cork like some folks prefer) it doesn't mean the rod is not loading. It simply means that you are expecting the rod to do something it was not designed to do with most casts.
Since you are feeling like the 1409-5 is underloaded and the 9/10/11 Windcutter actually overloads the rod a bit, you might be better served with a more moderate action rod that bends into the butt more readily. The 8/9/10 Windcutter has a weight of 585 gr over its 55' belly so any line and it is the Windcutter I would use on the 1409-5. The 700 gr Skagit head should be just about the right weight for the rod as well, that is why you were able to cast 90'-100' with it.
The good news is that if you keep practicing with your 1409-5 and the Windcutter 9/10/11 that you have (which is Simon G.'s "B" or heavier line suggestion for the rod), you will find as your technique improves and you become used to and comfortable with the faster, stiffer 1409-5 that you will be feeling the rod load and unload. In other words, you will grow into the rod as you spend more time with it, casting it, and learning its nuances. I can guarantee it won't crap out on you and have the tip fold with the type 6 and type 8 sink tips included with mutli-tip lines.
It likes any of the 8/9 short-belly (like the Windcutter 8/9/10, SA Short Spey 8/9, or Delta 8/9) spey lines; the 8/9 mid-belly (like the 8/9 MidSpey, 8/9 Sa Mastery Spey, or 8/9 Long Delta) spey lines; the 8/9 long belly lines (8/9 Accelerator or 8/9 Airflow Traditional); or the 7/8 extended belly lines (7/8 GrandSpey or 7/8 SA XLT).
