I rent for 3 accounts and can easily get all 3 to the Gold 3 league. BUT I've done so much better with just staying in silver 3 for the season-end rewards. Yeah, it's awesome to open all those chests but I've only been disappointed in the rental especially after paying so much for that last-day rental cost.
I'm just hoping once the new cards are playable I won't have to rent as much as I do now.