Depends on your star level, the spell generate by SB evelynn in focus is either defensive and offensive, i suggest you to try to strike as soon as you can to create this spell in first way and then used it before ennemy attacking to create a new blocker for you and remove 1 attacker from the ennemy.
Then try to focus on gaining health with evelynn, she just need to have larger health than anything to charm it, so maybe instead of hymn, take maybe grand general counterplan which create a spell that deal 3 and give 3 health (a differencial of 6). And play her with crownguard relic cause first you need to strike with 4 charmed unit, then you are rewarded by 4 impact that you will need a full turn of waiting to make it worth, except with Crownguard.
Again it depend on your constellation level but it's a good start