Suggestion: switch runes/masteries in-game with the Practice Tool

Hello RIOT. I am happy that you brought us the practice tool, as it is very useful and I thank you for that. However I have a suggestion. I think it would be a nice addition to be able to set runes/masteries in-game, even if we do not own them. That would help us decide "hm, is it worthy to invest **** IP in lethality runes for Wukong" for example, as well as instant "so, between level one and 4 Thunder is more efficient than Fervor on Lucian, but after that fervor outscales". No idea if it is actually correct, and testing it with different sets of runes/masteries would require a few logging in the testing tools, and the idea behind the testing tool is to save time. I am not sure how hard it would be to actually implement that, but if it could happen relatively easy it would be a great addition to the tool, at least IMO. Thoughts?