I'm not sure if this is a Clinton technique or not but get her into a trot for about three steps then shut her down, repeat and add length when you and Nova feel comfortable. Might be an option.
With the lunging yeah don't blame you at all then for not having her walk up to you. Like I said you are doing a great job with her it seems, hell, I'd be asking you for tips if I had a horse that needed work. Just don't have the time, or more so finances for one at this point in my life, good thing I have friends with them and can go see our old boy Jack whenever I want lol.
I do NOT want my horses ever walking up to me on the lunge. When I say whoa, it means whoa and stand until I give you another command.
I'm sorry I didn't clarify myself enough on what I said. Yes that is exactly what I had meant with coming to you, there needs to be a signal for the horse to come to you. I can't remember exactly what I use at the moment, actually have to lunge the horse to remember.
Wow there were a lot of "I's" in this post, sorry about that, not really a self centered person.