I would always do a protein treatment a week before my texlaxer, one during the mid-relaxer and then one within a weeks following a relaxer. Fortifying my fine strands is critical before, during and after a relaxer.
Now the question is when do I give myself a hardcore protein? I tend to do them just before a relaxer session. I would use the moderate strength protein during and after the relaxer. My mild protein treatments are generally done weekly, all other weeks.