I doubt the 4-element reducer will correct the CA from the 107FL design. From Ted's LRGB/OSC photos it seems like there is still some bloat. If I wanted truly excellent correction at such a fast focal ratio, I'd go for the FSQ-106 with f/3 reducer. Somehow I doubt the Borg will even come close to touching it. Hopefully someone will take the plunge and let us know!
With all due respect, the F3 reducer for the FSQ106 is not of the best optical quality IMHO, nor is the Reducer QE built all that great (grub screws.... bad idea). The Reducer 645 is a great piece of equipment though, but costs $2500. Compound that with the Fisher Price quality focuser on the FSQ and it is really difficult to recommend that system to anyone that is imaging with something heavier than a DSLR camera. Collimation has also plagued that scope, and others that are of the same design. With a full focuser replacement and good collimation though, the FSQ is a champ. That is a lot to ask of someone to accept IMHO.
I personally sold my FSQ and TOA, and replaced them both with a AP 130GTX. Reduced with the Quad TCC its very close to the same FL of the native FSQ106 (585 vs 530), 24mm of additional aperture and a smidge faster at F4.5. With the field flattener, its F6.7 873mm, which works great as well. But.. of course that is an expensive option and I dont think Jon is looking to invest that much.
The term "wide" needs to be defined here though. There are other options, such as using the Quad TCC on a TEC140 (F5, 705mm) which would be 1.43° x 1.08° and 1.11"/px with the ASI1600 and 1.07° x 0.71° 0.7"/px with the ASI183MM. My guess is that Jon is looking for something more in the 400-500mm range.