Currently on Level 115, I am capped at 408, it will take me 600 gems to add an additional 5.
I play as a collector, so I've managed to hold onto one copy of every 3* and above I've acquired on my roster. Dupes are not kept, I am only temporarily holding onto dupe 5* I get to exchange for Soul Exchange. I currently have 6 free roster spots left to collect feeders from the various training camps. It is a good thing costumes don't cost roster space.
With the number of heroes in this game, they should definitely be more generous with the ones being given at every other level ups.
