For those who may head this route, let me share some of my thoughts now that I am done and satisfied with the outcome.
I started with a T1100 Fulton winch with a 20' strap. It worked fine but had a 4.1:1 ratio and 7 inch handle. It took a lot of easy cranks to get the strap wound in. That winch had a defect so I returned it. I then bought a Fulton T600 winch that didn't include a strap. It was rated to only hold a 15' strap but I found THIS 20' STRAP
at WalMart for half the price and it is also a little thinner so it fits on the T600 perfectly. The T600 has a 3.1:1 ratio and a 6" handle. I just tried it out and it loaded up my TI complete with my 29.5# motor on the back just fine. The different ratio and shorter handle did away with the "too much cranking syndrome" but was still easy to crank.
I like the strap versus a rope because it winds up neatly and came with a sewn loop for attachment to the winch and a sewn on hook for attachment to the boat. There was no problem with stretching.
Given the added weight of the motor when installed and the fact that I have three cradles instead of two, it does take a good bit of force to pull this rig up onto the trailer. The built in handle may well work, I don't know...but if it were to pull out of the hull it could be very difficult to cleanly fix. I decided to use a harness of 1/8" Dyneema with a breaking strength of 2500#. It's a little hard to see in the picture, but it loops around the outer mounts of the front crossbar then threads through the shackle that holds the front of my spray skirts. I slipped the handle through the loops on the end of the Dyneema to keep it in check. The Dyneema has almost no stretch so it doesn't pull on the handle when winching in the boat. In the next pic you can also see a short piece of 1/8" nylon rope that I use for my stake out pole. For safety's sake I put it on the strap hook as well to stop the hook from doing damage to me or my vehicle if the Dyneema did happen to break.
P.S. Before anyone catches it ... I know the Trailex Winch Post it not mounted correctly. When I put this trailer together I told myself that I would replace the cheap lights that came with it over the following winter. Of course I did not - I left them until one day when it was around 100 degrees and wasted an hour sweating in the yard to get them to work so I could take the boat out. I finally got around to totally redoing the lighting system which entailed running all wires inside the frame, using waterproof LED lights, sealed connections and ground wires to all from the tow vehicle instead of grounding to the frame. That made it so I couldn't move things back any further without drilling another hole in the frame (Trailex says that's a no-no to start with) and redoing the wiring for the marker light. I also cut down the winch post to give more clearance for opening the hatch on my tow vehicle. This also makes the winch pull the bow down into the bow stop rather than trying to pull it up it. I used to just have a bungee cord holding the bow to the bow stop and it bounced a lot going down the road, it looks much happier riding now. It is rock solid as shown
EDIT: I have since changed the "harness" to 3/16th Dyneema with a breaking strength of 6,050# and made spliced loops that attach to the crossbar instead of looping around the crossbar mounts with two ends up front.