No problem "Old Man"
I'm good with Fireblast over Fireball. His abilities are to manipulate flame into things he can imagine and the size and power are reliant on his concentration. This can be represented better by Fireblast in that it would take less concentration for something small for a 2 dice attack and this would have a better chance of him rolling 2 skulls and attacking again. The higher concentration 4 dice attack would be less likely to get a second attack from rolling all skulls.