I'm certainly curious to see your updates on returns. I've never looked into rentals myself more because I feel like it would be time consuming to do so, especially not knowing which cards will work well together. I'm only slowly learning that through playing and seeing what my opponents are doing that works. I thought this was rather clever from someone who was spamming Lorkus, and I can see why:

https://splinterlands.com/battle/sl_d5d8fd713e11a042450168673aa21b0f?ref=life-relearnt

How much time do you think it took you to do all the rentals?