laverdure, if you're going to work at magnifications in the range 1:6 to 6:1, look for a 105/4.5 Comparon in #0 shutter. They can be found, usually for < $50 and according to Schneider work better in that range than the equivalent Componon and Componon-S. See, e.g., I have one, and it is easily reversed by swapping the cells front to rear.

If you can afford a 100 WF Ektar you can afford a 105 Comparon too.