support secondary should get sup < 40% of the time
Problem: If you put support as your secondary role, you get it 60%+ of the time. So you don't put support as secondary, because it means you get support too often. Therefore, we have even fewer supports in the queue.
For example, I would gladly queue Jungle/Support. However, when I do, I get support 60%+ of the time. So I queue Jungle/Mid instead, because it increases my Jungle role rate.
Solution: Change it so players who put support secondary, get it <40% of the time. This will encourage people to put support secondary, making more supports available.
This could be extended to secondary in-general, by making it so you will only get secondary <40% of the time, period. After all, our primary role is our main role for a reason. We want to play it more often.