Thank you. My mistake, the skirt was irrelevant, though I will now look into using one after you pointed out its usefulness.
I presume the perimeter extruder means the extruder that prints support material? If so, does it function correctly and prevent warping, if it is wide enough?
Anyway, from what you tell me I do not need to model a skirt, just let Slic3r apply it.
Sorry, I don't understand the third sentence, regarding wipe and prime tower.