At season's end I usually sit around 125%. It's all about farming rests.

If your conditions reserves are low, tanking a season is always an option. Last time I tanked, I repeated level 26, where I ended that season @ 129.4%. I had 300 rests at the time. The following season, I ended up reaching 137.7% and got my conditions up to just shy of 1100. Then at the end of the following season I ended around 128% and had 1800 conditions. As Nik said, with a low 7* team you can win pretty much anything in this game.