Jimib, the main advantage to doing the 'edit' work that you describe in Resolume is that you can make changes on the fly rather than have to re-render your media over and over. If you haven't already, make sure you take advantage of the keyboard shortcuts I & O that let you set your In and out points in the timeline based on playhead position. Also, when you click on the the playhead, you can enter the exact position you need MM:SS:MS where MS is in milliseconds.
Joris, when you click on the playhead arrows, it would be great if the increment could be one frame rather than 40 milliseconds.
Another way to do what you are doing is to use the layer router. You would set the duration of the various layer routers to the lengths you need and set the the autopilot feature to play the next clip. Take a look at the attached comp.
I used the Orange-Strings-07_720p_DXV video clip available for download at:
http://resolume.com/gfx/dxv/OrangeStrings_720p_DXV.zip.
Let me know if this is not clear.