Chemistry - Thinkwell with Zumdahl Text?

[Shelly in VA]

Ds is slogging through Thinkwell AP Chemistry this year, and it is not going well. His scores are fine, and he seems to enjoy the rigor of it, but the multiple choice format of the exercises is not resulting in a solid grasp of the concepts, in my opinion. I have had him use the Zumdahl textbook when he has struggled, but I am thinking of switching to the text as our main portion of the course and supplementing with the Thinkwell lectures and tests. I'd assign problems from the book and ditch the Thinkwell questions. Has anyone done this? Is it a bad idea to switch mid-year? Also, is there a resource anywhere that correlates the book with the lectures? That's fairly straightforward, but if it's already out there somewhere, that would make my task easier.

I should ask, too, if anyone has had similar issues with Thinkwell and comprehension. This is the 3rd kid I've had go through Thinkwell Chemistry, and I was very happy with it the first two times. Ds just seems to be tackling it differently.

Thank you! 

[BusyMom5]

I have not used Thinkwell, but I am using Zumdahl World of Chemistry for my Junior.  The textbook has a lot of questions to work through.   I have the teacher textbook that has all the answers in it and a teacher disc that has tests.  I do teach it to my kids lecture style.   I think its a good book- easy to understand but thurough.