I like this idea as belt and braces. I have a pair of TEX 'Wedgelock' wiper arms on the 4A (Part nos. U70944 and U70544) and they clamp firmly to the wheel box spindles. However, one frustration is that these arms cannot be pulled away from the screen and be retained in place, as can the original type of arm, facilitating cleaning of the screen or testing the wiper operation. Strangely, wedge lock arms for the TR6 do have this facility, as shown.
Tim