I feel like playing your creatures, hoping they survive, only to cast Henge and hoping to draw more creatures is a lot of hoops to jump through. The main draw of a card like this is the card advantage and I would rather cast Project consistently for 4 rather than messing around with Henge once I've already dumped my hand. Because Henge is so hard to cast I feel you're giving up too much value just trying to get it on board when maybe Galta would just end it there.
**Edited for clarity