I've heard of people using up to 320F or so for a few minutes for activation. I think some cannabinoids can start to vaporize in the mid 300's, so definitely lower than that.

If all you want to do is dry it, then I would try the 200F. That is not too hot. Preheat to 200F so that the temeperature does not fluctuate as the oven heats up. Then just put in as much as you want to smoke right now, or are willing to "risk." (Not really all that risky!) Keep checking it, and pull it out when you think it is as dry as you want. Don't get stoned and forget it's in there!

If you are really worried, use a lower temp. My oven goes down to 150. I would think that would dry anything out pretty quickly --- at least as fast as leaving it in the sun.

One last note: When I used 200F, it started to get really aromatic, so I had to run the kitchen vent fan. Don't try it if you need to be sneaky, bacause it will smell up your house a bit.