Yep, we got it. Without hesitation our suggestion of using some work time to improve our professional selves was accepted.
Most parts of our discussion was spent on implementation details. We argued back and forth between fixed time slot and free placement. The end result was to go for the free placement, since you really can’t force ideas and innovation to arrive at a fixed time of the week. Free placement simply means that at the daily standup a person asks whether it is okay for him to use his slack today regarding the sprint work and others so that his creative slack does impede any other team member. I even used the term gold card from an article I read a long time a go. Now I am considering of actually getting us some physical cards that can be used as symbols of taking the creative slack time.
We agreed that creative slack will give way in urgent cases, but that is acceptable. We have customers that need support so no problems there. We also agreed that the time that can be spent on creative slack is roughly half a day within one two week sprint. The scope of creative slack was also narrowed down so that it must relate to our work and professional skills at work. We now have the trust and as a team must take the responsibility that creative slack time is not used for slacking.