As previously mentioned, later type VVSS units on this build with the upswept return roller as can be seen in comparison with an earlier type below...

Tasca/Asuka units are really good, but do require a little TLC. There are some annoying joins between parts to deal with. The one at the end with the return roller assembly is particularly annoying due to its location. Using filler is awkward due to access so I've found the best solution is a piece of stretched sprue works best....

Once the cement has fully cured, a sharp blade is used to carefully shave the sprue away leaving a smooth face.
Standard filler is used for the other parts and styrene strips fill the void usually occupied by the kit track skids which will be replaced with PE items. I've also added the spring adjustment points using Meng styrene nuts...

ET Model provide a very useful PE template for drilling out the 4 holes on the leading face of each unit....

PE track skid added. I've used styrene bolt heads shaved from the kit parts. (Bolt heads are also added to the roller return bracket but not shown here)...

Completed unit....

Gary