Is this dict really a memory hog if it gets larger? Why not just set to a large number and move on? Just because we can make a double caching structure doesn't mean we should. Given that we have had very few complaints of this nature, my assumption is that most people are not hitting the 50-element limit, so bumping it to 5000 for the few people who need it doesn't seem like a terrible idea.

Note that this largely catches users who have accidentally used categoricals and created thousands of ticks. I think, if anything, we should add logic in the categorical ticker that raises a warning of more than 100 ticks are being asked for.