So How Can I Practice a Specific Champion on the Rift?

I keep trying to solo queue up in Normal with a goal to practice one specific champion in a role, and to increase the champion mastery. This would not have been a problem in the old Team Builder. If Dynamic Queue is "an improvement", then why am I having a hard time being able to achieve my goal? I have tried all three other roles as Secondary (excluding Supp of course), and last 4 out of 6 games have been wasted by having to play the role I'm not trying to practice at the moment. I'm fine with the Dynamic Queue and how it works in Ranked...but I'm ONLY playing Normal for one specific reason, and it isn't very fun to waste 2/3 of your time. I have not tried Blind Pick yet, but I can't imagine that would be better....basically just relying on random chance that I get first pick. From reading how the Hextech stuff works, this problem could be even bigger. People will only want to play champs they have not earned the chest on yet, no matter what role they are assigned. I realize one answer is Party Queue with 4 other people, but that isn't an option for me. So for those who claim Dynamic Queue is an improvement on the Team Builder in all aspects, please let me know how I can get better at a single champion on Summoner's Rift against human opponents, without having to spend two out of every three games not wanting to be there. MY opinion is to bring back Team Builder, but make it only an option for Solo. People who want to Queue with friends will still need to use the Dynamic, but it allows for someone to practice on their own time.