I didn't do that myself but I think it's a very valid strategy. The only problem I can see is that it might hurt your momentum: sometimes you just need to go ah

I didn't do that myself but I think it's a very valid strategy. The only problem I can see is that it might hurt your momentum: sometimes you just need to go ahead and write without having to wait for feedback or A/B test results for every chapter. Same with presales, it's a great strategy as long as you don't spend so much time promoting the pre-sale that you forget to write the book! It might sound like I'm exaggerating but there is so much you can do to market eBooks that the book itself can sometimes become almost an afterthought…