I would encourage you to drop the 40-minute limit on postings. Allowing people to only post once per 40 minutes means that for many users they will only be making one answer (or question).
I am not going to sit around logging on every hour throughout the day.
When I visit a particular SE site, I do my work and then leave and may not be back until the next week or maybe even the next month. My whole time budget for a visit might only be 15 or 30 minutes. So, saying I can only make one post when I visit is, I think, a bad policy and I know of no other SE site that does this.
Today I made 2 identification questions and I was able to re-visit an hour later to make the second one, but that was an unusual case because it is Sunday. During the busy work week, if I have multiple questions and/or answers I am not going to be running an egg timer an re-visiting the site 6 times throughout the day.
Even for people with 0 reputation, I think this policy probably hurts the site more than it helps it (are you really so fearful of spam you are willing to lose genuine questions and answers to cut down on spam?), and for people like myself that have 100 rep because we are "trusted" on other sites, it makes no sense at all to me.