Thanks for stopping by to read my post and for the encouragement!
I tried to just do the daily quests but they are not enough to get to higher leagues in a short timeframe and as I like this game, I bought SPS and decided to go this route. The advantage of the method I suggest here is that you do not put your budget at risk by buying cards that might end up not being useful for the strategy you want to pursue. Instead with this method you only use the interest generated by leaving the SPS in staking. The other advantage being if you realize the rented cards not to be good enough you can change strategy (and cards) on the go. I feel like this method can be a better way of "grinding" cards and get into higher leagues.