[Solved] Making mobile non harvester not attack

[noob]

I have mobile non harvester units with temporary lives(and that are very slow) and I want the custom ai I am making to exclude them from picks for attacking but still use them for recruiting units.
How do I do that without using non ai scripting (I do not want to spend calculation resources nor to make the non ai triggers more complicated for that)
edit: I found out it was the fact the unit was temporary that made the ai consider it was an assault unit.
now I have a new question : which parameter should I tinker with in terms of attack waves if I want to not have attack waves stalled enormously when the base constantly produces units?