The former Everton centre-forward joined Leeds last month as a free agent.
"I think we have enough firepower to stay up, but there's always a concern," Evans said. "Every promoted side has that concern of scoring. At the same time, the goals you allow are important.
"It's always a trade-off of adding defensive firepower versus offensive firepower and getting the balance right. I do think that our strategy this summer was balanced towards both those things.
"The goal is to win 10 games - I think we're capable of winning them."
On convincing Calvert-Lewin, Evans added: "We're very proud of the way we went and got Dom, who, by the way, turned down a Champions League contract the day we signed him. We're thrilled that he's here.
"A shared view from the manager, from the recruitment and from the sporting director was that of all the options that were even plausibly available to us nobody was a better fit to the objective of staying up this season than Dominic."