I think our strategies are similar.
I have bought all the Rebellion ( almost all, not got the really expensive ones like Akane yet) I think I need for my deck. As I play I might discover I need a card that I wasn't initially drawn to, but time will tell.
My CL deck is gold and I consider myself a Gold League player, however this is not strictly true any more, as I cannot get out of Silver in Modern yet ( still in Bronze this season), so the max level I have for my Rebellion cards is Silver, , I feel the longer I wait the lower card prices will be
When I do eventually get back into Gold Modern, I will look at levelling the most impactful Rebellion cards.
So no new wagons needed, I'll "beef up" the wagons I have in the future