Why do you plan on doing this treatment? IIRC, pyrethrum is not a repellent, it is a toxin both for insects and for humans in sufficient quantity. If your tent has a reasonably good zipper setup then bugs won't get in enough to cause problems and an insecticide treated footprint would not be of any help.

It seems to me as though you may be trying to solve a problem you are not likely to have and would be exposing yourself to low doses of a potentially toxic compound in doing so.

Pyrethrum evolved as a toxic compound to keep the chrysanthemum in which it evolved from being eaten: by insects or by animals. This is one reason that I avoid pyrethrum treated clothing, the other reason being that I have not found it necessary.