The rudder fittings are "the most simply that are practical" I.E the top and bottom fittings on the transom are stainless pins set in an aluminium casting (standard, off the shelf fittings) and the rest is a top and a bottom hole drilled through the carbon fibre/ Kevlar (50/50) that the stocks are made from with a moulded shape allowing for those holes. We like to simplify EVERYTHING as much as practical so that the greatest percentage of our boats can be built "in house". Saves a lot of time and expense. It's also nice not having to rely on multitudes of "outside" suppliers.
The T foils seem to have no noticeable effect other than those already described, the windward and leeward performance as regards pointing/leeward drift, appear to be the same sailing with T foiled rudders or without, the foils work the same with the cat heeled or not, and lifting one rudder completely out of the water has no different “feel” or movements than the same without foils, over “long swells” the foils tend to keep the decks parallel to the “average” water surface therefore traversing slow, long changes to the surface (as in long swells) the hulls will follow parallel to those change, but through “chop” the decks stay level and instead of the bow going up and down, the whole hull rises and falls -level- (but with much less movement overal than with the "pitching" motion of a cat without foils) also without the (nodding dog) rocking.