At that stage, I had to come to the constatation that my "scratchbuild" was not perfect: the wheels and tracks are 2mm too high. It's not enormous, but sufficient enough for me to correct the work for the master. My error came because I copied the position of the elements of the Revell's Marder, but as said, the wheels have to be positioned more lower.
Another fact came also: as Dominique Jadoul said to me, to "scratch" work on two similar tanks is a kind of waste of time. So I've decided to put my "scratch" in reserve (eventually for spare parts) and to concentrate on the master.
And it's here I am. After february I will re-start the work for the master and, of course, will keep you posted...