Need help with Mounting of Internal Rollerblinds

Need some help with mounting of internal roller blinds on 4 of our windows. We already have the roller blinds but they are slightly wider than the windows and so must be cut to fit the window size (maximum of 5-10 cm) Looking for someone who can do tidy job : ) Note: There are some restrictions as to where you can drill around the windows. See attached image & the comments from the builder Comments from the builder: Leilighetens yttervegger er utstyrt med dampsperre bak gipsen. Denne må ikke punkteres ved oppheng av gardiner. Skruene må derfor treffe i stenderverket som gipsen er skrudd i.» Hvis man måler 8cm fra vindu smyget vil man treffe midt i stolpen. Gjelder rundt hele vindu.