When they started getting white I would just put a few on branchs or vines. I always try to hand feed the first few. Cup feeding never worked as the can climb out.
I saw a post a while ago where I saw a shallow dish on the plants. If you put some silkworms in a dish on the plants and they crawl out they will be hunted. So would be fine as they can eat from the dish and hunt them down. May be an issue if you put too many in at once though.