Save your tabards. As everything here is mostly RNG, you may never know which powerful 5 star purple may land on your lap since you are C2P and may have some amount of gems once in a while, not to mentioned that all events have tokens or coins to pull heroes to (keys, atlantis coins, event coins), easily obtainable from quests or the event itself. However, if you happen to get your tabard count to at least 11, go ascend Quintus. The view that you level available heroes in your roster or the best hero is the one that you have, in my honest opinion, are only mostly applicable to F2P players where they barely summon at the portals compared to C2P and P2W players. C2P and P2W players, by reason that they have more gems than F2P players, have more chances of summoning ideal heroes. I suggest you build up more of your purple 4 stars, i.e. Rigard, Proteus, Tiburtus, Cheshire Cat, Ammeona, and some of their dupes.