It's 2 years old now. I just thought it was interesting because it suggests maybe a straight dominant/recessive inheritance pattern... maybe... Lilac Charm (thorned) x Legacy (thornless) --> Carlin's Rhythm (thorned) x Carlin's Rhythm (probably) --> OP Carlin's Rhythm (thornless). It wouldn't be that simple would it (ploidy aside)?
It probably doesn't work that way often, but why couldn't it occur some times? You've seemed to fix the character you desired in it fairly easily. Now, to see if it is stable enough to transmit further..