I'm heartless, so when the chicks got moved to the coop, I put them in (a cage for 2 days, as I have hens), shut the door, walked away and let them scream until it was dark and they finally gave up. They got over it.
Roosting will probably take some time. Some groups of chicks figure it out...
1/4" is usually thinner wire so less strong than typical 1/2" but I'd say generally it should be good enough on most coops against most predators.
All my windows have 1/2" HWC, but all other vents (under eave, gable, floor, ridge) have 1/4".