Glad to hear that the Tough Resin is continuing to improve for you! The switch from Tough V3 to Tough V4 Resin was a bit different from these. In that case, a component did change which influenced the mechanical and aesthetic properties. The difference between the two materials was slight which is why users were able to mix the two formulations without error. I’m a bit surprised to hear that your results are significantly better with Tough V4 Resin but certainly glad that’s been the case!
For each of these re-formulations, the components will remain the same and the only difference is a change in supplier. Mechanical and aesthetic properties will be nearly identical and these will be mixable with the previous formulation.