I'll be honest with ya, I'm not sure if it'll shock the plants. My gut feeling (if it were me) would be to ride it out with the 600 for now. I'm not the best person to answer that one.
As far as the turkey bags, I would think they wouldn't be any more prone to mold than jars. If the bud is molding in the jar that's an indicator that it needed more time to dry, or it molded during drying and you didn't notice it until the jar. I wouldn't let that thought deter you from trying it out for yourself. I too used jars for a long time, but as my growing style produced more buds I found it to be a more laborious job to cure. That was when I got online and saw commercial growers managed large quantities of herb and applied that to my system. If you're only curing a couple OZ then I'd say it makes no difference, but when I have 1-2 lbs at a time, jars become my enemy.