How much you should spend depends on your budget and how much you want a hero.
I would advice take into consideration a fixed budget for the month (or whatever period that makes sense for you). And then split this budget between events, depending on the heroes you want the most. I would say there are 5 events to consider:
- Atlantis rise
- New costume release
- Tavern of legends (right this month?)
- Valhalla portal
I do not have an answer and I’m also searching how I should spend my gems during May.
Was also initially interested by GM, but now I’m hesitating. I already have JF. If I save these 8400 gemms because I should live with JF instead, then it might be interesting for me to spend a bit in other events.
Of course, we all want to maximize our chances to get new worthy heroes.