If you water twice a day, that is plenty.
Not trying to knock your advice, and I'm no expert by any means, but in my experience, that's not enough drinking opportunity for the cham. Not only that, but that may not be efficient enough humidity.
OP, if you're home all day, or for the majority of the day, hand-misting is fine. Has your cham pooped yet? That's another good way to find out how well hydrated it is. If the urate is yellow/orange, it is dehydrated. If it's white, it's fine.
put it this way, when i first got my cham, I was in the same boat as you. Except I had to work 9-5. I'd spray before work, then come home for lunch, spray for a good 4-5 minutes, then go back to work, then spray when I'd get home, etc.. That WASN'T enough. Koop's urate was orange.. I bought a MistKing immediately, and I have it spraying about 5 times a day, pretty much every 3 hours or so.
The more opportunity you can offer your cham to drink, the better... This is, of course, as long as you give your enclosure a chance to dry completely, which prevents bacteria from breeding/thriving.