I researched the aero screen issue over a year ago, purchased all the parts, but have not yet installed them on my 56 TR3 with a dzus attached windshield. The car has the original-placed capture nuts in the cowling with replacement chrome headed bolts.
The Moss Trophy Tourist screens are what I purchased. Supposedly, they will not fit the capture nut spacing on the car, as there is a difference in the width, maybe up to 1/8th of an inch. The solution I chose was a set of brackets from Peter Wigglesworth in England that adjust for the width as well as come with various thickness fiber washers. Peter also tells how to add the rubber piece to the bottom to keep wind and rain from going under the aero screen (TRF part numbers and detailed description). The eBay offering a couple entries above appear to be an exact copy of the package using Peter's solution. With shipping, his brackets were 127.25 BP. They were very high quality and his instructions were precise.
I just finished a side screen project, so it is hard for me to think about pulling the windshield and installing the aero screens, but it is only a little water, or was that "only a flesh wound?"
Good luck and let me know if you want to contact Peter or would like the part numbers for the channel or rubber trim to attach below the aero screen.
The car in primer was what Peter sent me as an example of fit. The blue side screen picture is my car.